Covalent switching, involving divinylbenzene ligands within 3D coordination polymers, indicated by changes in fluorescence.

Reversible cycloaddition reactions between 1,4-bis[2-(3-pyridyl)ethenyl]benzene and its photodimers were performed within a pair of three-dimensional coordination polymers with retention of single crystal character. In each case, switching between two crystalline forms could be followed by monitoring the flourescence behaviour.