Gold nanoparticles functionalized with iron(II) terpyridine complexes undergo upon laser flash excitation long-lived charge separation in both conventional organic solvents and ionic liquids. The nature of the transient species depends on the laser excitation wavelength, 308 (Fe(tpyR)(2)(3+) and Au-) or 532 nm (solvated e-). No transients in the microsecond timescale are observed in acetonitrile upon excitation of gold nanoparticles lacking iron(ii) terpyridine complexes. The photogeneration of long-lived transients upon irradiation of these functional gold nanoparticles has been applied to develop an integrated (light harvester plus catalyst) visible-light photocatalysts for H2 generation from water that does not need methyl viologen as an electron relay.