In this paper, we investigate the light-induced electron transfer dynamics of prbimRuPt and its mononuclear counter part prbimRu using steady-state and transient absorption spectroscopy, along with time-dependent density functional theory (TD-DFT) calculations. Additionally, we examine the catalytic activity of prbimRuPt with respect to proton reduction and compare it to the structurally analogous systems [(tbbpy)2Ru(tpphz)PtI2] 2+ (tbbpyRuPt) and [(fbpy)2Ru(tpphz)PtI2] 2+ (fbpyRuPt), as their fundamental photophysics is well understood. By comparing these systems, we derive general conclusions regarding the impact of peripheral ligands on the catalytic performance of Ru-tpphz-Pt photocatalysts.