A PtCl2(bpy) derivative tethered to two viologen (MV(2+)) moieties drives photochemical H2 evolution via forming a three-electron-reduced species possessing a bpy(-)˙-based (or MV(0)-based) reducing equivalent. Such species can only form after one electron reduction of both the MV(2+) sites because of rapid intramolecular electron transfer from bpy(-)˙ to MV(2+).