Time-resolved Raman spectroscopy has uncovered a new type of photoinduced intermolecular electron-transfer reaction of biphenyl in alcohols. The Raman bands of the first excited singlet (S-1) state, the cation radical and the anion radical of biphenyl were simultaneously observed in the time range 0-200 ns after photoexcitation. The two ion radicals exhibit distinct rise and decay behaviors from each other. A kinetic analysis shows that the electron-transfer reaction consists of the following three elementary processes; (i) monophotonic formation of a biphenyl cation radical and a solvated electron via the S-1 state, (ii) migration of the electron in the solvent medium, and (iii) anion radical formation resulting from the capture of the electron by a biphenyl molecule in the ground state. The formation of the cation radical from the S-1 state is a slow process with a rate not greater than 10(-7) s(-1).