Ultrasensitive Photochromic Iodocuprate(I) Hybrid

By employing in situ methylnicotinohydrazide dication (MNH²⁺) as an electron acceptor, we have constructed an iodocuprate­(I) hybrid {[MNH]­[Cu₂I₃]₂}_n (1), which exhibits charge transfer (CT) thermochromism due to the intense absorption of CT and electron transfer (ET) photochromism with high photocoloration contrast and fast response to UV irradiation due to the synergetic effect of valence change of copper ions.