The influence of ionic strength variation and of exciplex formation between silver ions and triplet excited RuL32+ (L = bipyridine, phenanthroline) on the photo electron transfer kinetics of the complex with methylviologen and the magnetic field dependence of free radical formation efficiency has been studied by laser flash spectroscopy. The magnetic field effect consisting in a decrease of the efficiency of cage escape eta(ce) in the Ru(bpy)(3)(2+)/MV2+ system is enhanced by 40% when exciplex formation between Ag+ ions and tripler excited RuL32+ complexes takes place. The relevant kinetic parameters have been determined by magnetokinetic model calculations.