A new type of cyano-bridged Co−W bimetallic assembly, CsI[{CoII(3-cyanopyridine)2}{WV(CN)8}]·H2O was synthesized. This compound exhibited a temperature-induced phase transition and a photoinduced magnetization. Irradiating with light induced a spontaneous magnetization with a magnetic phase transition temperature at 30 K. This photoinduced magnetization is due to the phase transition from CoIII(LS; S = 0)−WIV(S = 0) to CoII(HS; S = 3/2)−WV(S = 1/2) phases by the irradiation.
