Photoinduced electron transfer between different coumarin dyes and N,N-dimethyl aniline has been investigated in ACT reverse micelle using steady state and time resolved fluorescence spectroscopy. We have observed a slower electron transfer rate in reverse micelle in comparison to that in the neat solvent. Moreover, we have observed retardation in the electron transfer rate in the correlation of the free energy change with the electron transfer rate. This unexpected outcome in a bimolecular electron transfer is assumed to be arising from the different diffusional rate of the reactants in the inhomogeneous ACT system. (c) 2005 Elsevier B.V. All rights reserved.