Transient absorption spectra of a zinc-tetraphenylporphyrin(ZnP)-fullerene(C-60) linked compound with flexible eight methylene groups indicated that intramolecular electron-transfer occurred in benzonitrile, while not in toluene. In benzonitrile, the decay rate constant of biradical decreases quickly in lower magnetic fields (< 0.1 T), and then increases gradually and finally become almost constant in higher magnetic fields (0.1 less than or equal to H less than or equal to 1.2 T). The magnetic field effects (MFEs) verified that the triplet biradical was generated from the intramolecular electron-transfer of the triplet-excited states of ZnP and C-60. The reverse phenomenon of the MFEs around 0.1 T is most likely ascribed to the properties Of C60 moiety. (C) 2004 Elsevier B.V. All rights reserved.