A viologen-based coordination polymer exhibiting high sensitivity towards various light sources

The self-assembly of a photoactive 1,1'-bis(4-carboxybenzyl)-4,4'-bipyridinium ligand with cadmium chloride in the presence of a strong electron-donating oxalate anion has successfully afforded a photochromic coordination polymer, which shows high sensitivity not only to ultraviolet-visible radiation but also to X-rays.