We analyse chemical reactions, particularly those occurring in biochemical systems, in order to develop new synthetic methods and to produce physiologically active compounds with potential as pharmaceuticals. We are also interested in the assembly of supramolecular systems. We design and synthesise molecules to modify the systems for useful purposes. Our work in this area has already resulted in pharmaceutical formulations that are in everyday clinical use worldwide. This chemistry also has applications in the development of molecular devices such as catalysts, reactors and photochemical and thermal switches.