We investigate the effects of encapsulation on the dynamics after photoinduced bond cleavage of a diphenylmethyl phosphonium salt in acetonitrile reverse micellar nanopools by femtosecond UV/Vis transient absorption. The small volume of the nanopool is just large enough to accommodate one precursor molecule and therefore eliminates the effects of diffusion present in bulk solution. The tight environment keeps the fragments together and prolongs the time for geminate recombination to occur. We therefore observe an enhanced yield of this bimolecular reaction of the ground state photofragments. (C) 2011 Elsevier B. V. All rights reserved.