Methylviologen dication was intercalated to some layered semiconducting oxides, and the photoinduced electron transfer between the hosts and the guest was investigated. K4 Nb6O17, H2 Ti4O9, and HTiNbO5 were used as the layered oxides. The arrangements of methylviologen in the interlayers were deduced from the XRD results. UV irradiation of the intercalation compounds caused electron transfer from the hosts to the guest to form methylviologen radical cations. The radical cations were stable within a few minutes even in the presence of oxygen, and the decaying rates altered with the hosts. The difference was discussed on the basis of the structure of the intercalation compounds.