The photoreduction of N-(p-benzoylbenzyl)-N,N,N-tri-n-butylammonium triphenyl-n-butylborate (1) and gallate (2) was studied using nano- and picosecond laser flash photolysis. An electron transfer reaction from the berate or the gallate counteranion to the excited triplet state of the benzophenone moiety (BP*(3)) was demonstrated. This reaction leads to the formation of benzophenone radical anion (6) and the boranyl radical, the latter of which dissociates rapidly to form butyl radical. The electron transfer rate was found to depend on the polarity of the solvent. In neat benzene, the short lifetime of the triplet obtained (300 +/- 150 s) indicates an intramolecular process and that the compounds exist as tight ion pairs. The addition of 1% MeCN increases the triplet lifetime up to 1.2 ns. The formation of a solvent-separated ion pair was suggested in this solvent mixture. However, in the polar solvent MeCN, 1 and 2 exist partially as free ions as determined by their dissociation constants. A diffusion-controlled intermolecular electron transfer process was shown in this solvent. The p-benzoylbenzyl radical (BPCH2(.)), most likely formed by the C-N cleavage bond in the radical anion (6), was identified as an intermedate in the reaction pathway. After the initial electron transfer reaction, this produced tributylamine. The quantum yield obtained for the reaction of 1, 10(-2) M in MeCN, is 0.5 +/- 0.05. Triplet quenching as well as coupling of the radical anion (6) with the butyl radical deriving from decomposition of the berate was suggested to compete with the C-N cleavage reaction.