The electron-transfer reaction from nucleophilic anions such as SCN-, N-3(-) I-, and Br- to the 1-pyrenesulfonic acid radical cation (Py(.+)SA(-)) generated via a resonant two-photon ionization process in the Nafion membranes was investigated with transient absorption measurements. The apparent quenching rates observed in the Nafion membrane (k(q)(Nf)) were almost 2-4 orders smaller than those observed in the bulk solutions (kq bulk). The attenuation factor (AF), which is defined as log(k(q)(Nf)/k(q)(bulk)), decreased in the order SCN- > N-3(-) > I- > Br-. This interesting behavior was interpreted in terms of the anionic Hofmeister effects. The effects of hydrophobic organic cations such as tetrabutylammonium ion (Bu4N+) and tetraethylammonium ion (Et4N+) exchanged into the Nation membranes were also examined.