Heterogeneous catalysts – materials with catalytically active surfaces – produce the fuels, fertilizers, and commodity chemicals that sustain us. However, catalytic processes are often constrained by economies of scale and come with substantial environmental impact. There is now an urgent focus on uncovering core principles of catalyst design that enable more efficient resource utilization. To this end, I am inspired by a foundational question: how can we manipulate the structures of heterogeneous catalysts to control catalytic function? Here, I focus on a broad and economically important class of materials comprising transition metal ions grafted to solid supports. I describe an innovative approach to catalyst design that tightly couples advanced spectroscopy with molecular inorganic chemistry and materials synthesis. By understanding and controlling catalyst structure at the molecular level, we gain footholds into many problems of outstanding fundamental and practical significance.