Inspired by the myriad enzymes found in living organisms, supramolecular chemists have investigated the cavities of both macrocycles and the related interlocked molecules catenanes and rotaxanes as catalytic and non-catalytic sites of chemical reactions. While macrocycles are typically easier to access synthetically, the interlocked structures of catenanes and rotaxanes offer exciting opportunities, including their innate three-dimensionality, large-amplitude motion of their interlocked components and chirality arising from the mechanical bond.