The fastest electron transfer processes between molecular donor/acceptor systems have been observed for solvent to solute type reactions, where the number of solvent molecules participating could be high. This might explain the very short electron transfer times of less than or equal to 100 fs observed. Here the photo-induced electron transfer in a bridged donor/acceptor system was studied by femtosecond pump-probe spectroscopy with a time resolution of 15 fs. After photoexcitation of the acceptor (nile blue) an electron is transferred from the donor (ferrocene) with a time constant of 90 fs, i.e. close to fastest electron transfer times in the solute/solvent systems. (C) 2002 Published by Elsevier Science B.V.