Photoinduced electron-transfer processes between fullerene (C-60) and 1,8-bis(dimethylamino)naphthalene, which is called a proton-sponge (PS), have been investigated by means of laser flash photolysis in the presence and absence of CF3CO2H. For a mixture of C-60 and PS, the transient absorption spectra showed the rise of the C-60 radical anion with concomitant decay of the C-60 triplet (C-3(60)*), suggesting that photoinduced intermolecular electron transfer occurs via C-3(60)* in high efficiency in polar solvent. For a covalently bonded C-60-PS dyad, photoinduced intramolecular charge-separation process takes place via the excited singlet state of the C-60 moiety, although charge recombination occurs within 10 ns. For both systems, electron-transfer rates were largely decelerated by addition of a small amount of CF3CO2H, leaving the long-lived C-3(60)*. These observations indicate that the energy levels for charge-separated states of the protonated PS and C-60 become higher than the energy level of the C-3(60)* moiety, showing low donor ability of the protonated PS. Thus, intermolecular electron-transfer process via C-3(60)* for C-60-PS mixture and intramolecular charge-separation process via C-1(60)*-PS for C60-PS dyad were successfully controlled by the combination of the light irradiation with a small amount of acid.