Photoinduced electron transfer processes between fullerenes (C 60) and four phenothiazine derivatives (PTZs) in the absence and presence of hexylviologen dication (HV2+) have been studied by the transient absorption method in the visible and near-IR regions. Electron-transfer takes place from PTZs to the triplet states of fullerenes (3C60*) giving the radical anion of fullerenes (C60•-) and the radical cations of PTZs (PTZ •+). The rate constants and efficiencies of electron transfer are quite high, because of the high electron-donor abilities of PTZs as elucidated by their low oxidation potentials. On addition of HV2+ to the C60 and PTZ systems, the electron-mediating process occurs from C60•- to HV2+, yielding the viologen radical cation (HV•+). In the presence of a sacrificial donor, HV•+ persisted for a long time.