Photochromism of a novel hexaarylbiimidazole derivative having azobenzene moieties

A novel photochromic hexaarylbiimidazole derivative with azobenzene moieties was synthesised and the molecular structure was determined by X-ray diffraction. The spectroscopic investigations for the photochromic behaviours revealed the presence of the independent four photochromic states, viz, triphenylimidazole dimers with trans- and cis-azobenzenes, and triphenylimidazolyl radicals with trans- and cis-azobenzenes.