Nearly 80% of the processes involved in the chemical production of bulk or fine chemicals employ heterogeneous catalysts that are typically solids. The heart of the heterogeneous catalyst is the surface active site which must be highly active, selective and stable during several hundred cycles of reaction. Although it is not always possible to determine the structure of an active site in a heterogeneous catalyst, the emphasis of modern day research has not only been to understand the structure of an active site but also synthesize and study them. The article will describe some of the challenges from this perspective with examples from the authors research. © 2019 Indian National Science Academy. All rights reserved.