Mandi : Professor Emeritus and Distinguished Professor at the Indian Institute of Technology Mandi, Gautam R. Desiraju, has been honoured with the prestigious 14th Ewald Prize by the International Union of Crystallography (IUCr) for his pioneering contributions to the field of crystal engineering.
The international recognition acknowledges Professor Desiraju’s influential work on crystal engineering, supramolecular synthons, and the structural significance of weak hydrogen bonds and halogen bonds in molecular crystals and biological systems.
The Ewald Prize is presented once every three years during the International Congress of Crystallography to recognise outstanding contributions to crystallographic science. The 2026 Ewald Prize was presented to Professor Desiraju on August 11, 2026, during the IUCr Congress held in Calgary, Canada.
Recognising Pioneering Work in Crystal Engineering
Professor Desiraju is widely recognised for helping establish crystal engineering as a design-oriented discipline of chemistry.
His research has focused on understanding how molecules interact and arrange themselves within crystals and how these interactions can be used to design materials with specific structural and functional properties.
One of his major contributions has been the recognition of the importance of weak intermolecular interactions, including weak hydrogen bonding and halogen bonding. Such interactions, once considered relatively insignificant, are now recognised as important factors influencing the structure and properties of molecular crystals and biological systems.
His work with Thomas Steiner helped establish the structural significance of the C—H···O interaction as a genuine weak hydrogen bond, culminating in their influential 1999 book on weak hydrogen bonding.
Supramolecular Synthons: A Landmark Concept
One of Professor Desiraju’s most significant conceptual contributions is the idea of supramolecular synthons.
He introduced the concept in a landmark review published in 1995, drawing inspiration from the retrosynthetic approach to molecular synthesis associated with Nobel Prize-winning chemist E. J. Corey.
The concept provided a new way of looking at molecular crystals—as structures that can be designed and assembled using predictable intermolecular interactions.
Instead of viewing crystal structures merely as outcomes of molecular packing, the supramolecular synthon approach considers crystals as synthetic targets that can be rationally designed.
This approach played an important role in transforming crystal engineering into a design-based and synthesis-oriented field within chemistry.
From Binary Cocrystals to Complex Molecular Crystals
Professor Desiraju’s research has also explored increasingly complex molecular crystal systems.
The development of the supramolecular synthon concept contributed to research involving binary and ternary cocrystals, and subsequently more complex molecular crystals containing four, five and even six different components.
Professor Desiraju has described such highly complex multicomponent crystals as the “Mount Everest of supramolecular solid-state synthesis,” reflecting the scientific and design challenges involved in creating them.
Potential Applications in Pharmaceuticals
The principles of crystal engineering have significant practical applications, particularly in the pharmaceutical industry.
Pharmaceutical cocrystals can help improve properties of active pharmaceutical ingredients, including solubility and bioavailability, without necessarily changing the active pharmaceutical molecule itself.
This approach can be particularly valuable for drugs that have poor water solubility. According to Professor Desiraju’s work, several pharmaceutical products based on crystal-engineering principles have already reached the market.
Crystal engineering can also influence other properties, including stability and mechanical behaviour, making the field relevant to both pharmaceutical development and advanced materials research.
Looking Towards Artificial Intelligence
Professor Desiraju’s recent work and reflections also address some of the major unresolved challenges in crystallography, including polymorphism and crystal structure prediction.
He has expressed the view that artificial intelligence could potentially make major advances in crystal structure prediction over the next five to ten years.
Accurately predicting how molecules will arrange themselves in a crystal remains a complex scientific challenge because of the large number of possible molecular arrangements and the subtle balance between different intermolecular interactions.
Research on Mechanically Responsive Crystals
Another emerging area of Professor Desiraju’s research involves mechanically deformable molecular crystals.
These materials can exhibit unusual mechanical responses, including the ability to bend, undergo molecular or structural shifts, and in some cases recover their original form.
Such research expands the scope of crystal engineering beyond simply understanding static structures and towards the development of materials with dynamic and responsive properties.
A Holistic View of Molecular Crystals
In a special article associated with the Ewald Prize, Professor Desiraju reflects on the development of crystal engineering and his scientific journey.
The article, titled “Crystal Clear. Engineering Complexity,” is published in the September 2026 issue of the IUCr journal and forms part of a special collection associated with the 2026 IUCr Congress.
Written in an accessible first-person style, the article traces his scientific journey and the development of ideas that helped shape modern crystal engineering.
Professor Desiraju also presents a broader philosophical perspective on molecular crystals, viewing them as complex, integrated systems rather than simply collections of individual molecular components.
According to this perspective, the properties of a functional crystal depend on a balance between the strength of strong chemical bonds and the adaptive flexibility provided by weaker intermolecular interactions.
IIT Mandi Welcomes the Global Recognition
Commenting on the honour, Professor Laxmidhar Behera, Director, IIT Mandi, said that Professor Desiraju’s Ewald Prize is a matter of great pride for IIT Mandi and Indian science.
He highlighted Professor Desiraju’s pioneering contributions to crystal engineering and noted that his research has expanded the understanding of molecular interactions while opening new possibilities in areas including pharmaceuticals and advanced materials.
Professor Desiraju also described the Ewald Prize as one of the highest recognitions available to structural chemists and biologists, highlighting the rigorous and confidential selection process associated with the award.
Distinguished Academic Career
Professor Gautam R. Desiraju is associated with several leading academic institutions. He is Professor Emeritus at the Indian Institute of Science (IISc), Bengaluru, and serves as a Distinguished Professor at IIT Mandi’s IKSMHA.
He has authored more than 475 research publications and has received over 80,000 citations, reflecting the global influence of his scientific work.
He also served as President of the International Union of Crystallography from 2011 to 2014.
A Major Recognition for Indian Science
The 14th Ewald Prize represents a significant international recognition of Professor Desiraju’s decades-long contribution to structural chemistry, crystallography and crystal engineering.
His work has helped move crystal engineering from the study of unusual or difficult-to-explain crystal structures towards a predictive, design-oriented scientific discipline with applications in pharmaceuticals, materials science and molecular engineering.
The honour also highlights the global impact of Indian scientific research and recognises Professor Desiraju’s role in shaping the understanding of how molecular interactions determine the structure and behaviour of crystals.
