A cationic coordination cage dramatically accelerates the Knoevenagel condensation of aromatic aldehydes in water under neutral conditions. The addition of a nucleophile to the aldehyde to generate anionic intermediates seems to be facilitated by the cationic environment of the cavity. The products are ejected from the cage as a result of the host-guest size discrepancy. As a result, the condensation is promoted by a catalytic amount of the cage.

Triquinacene is a concave tricyclic hydrocarbon with diverse photoreactivity. In the cavity of an electron-accepting molecular host, triquinacene was specifically photooxidized at the peripheral allylic position into an alcohol, 1-hydroxytriquinacene, via guest-to-host electron transfer. The unusual reactivity stems from the extremely electron-deficient triazine panel ligand of the host cage, which allows the cage to function as a good electron acceptor. Thus, self-assembled coordination cages can serve not only as molecular-sized reaction vessels but also function electronically as redox media. Dissolved molecular oxygen is indispensable for the photoreaction and immediately traps a photogenerated radical.