We have synthesized and investigated the bimetallic complex [(prbim)2Ru(tpphz)PtI2] 2+ (prbimRuPt), featuring N,N 'propylene-protected 1H,1'H -2,2'-biimidazole, i.e., prbim spectator ligands. This bimetallic complex complements the set of previously reported tpphz-bridged RuPt photocatalysts. In summary, the peripheral ligands play a pivotal role in determining the initial composition and subsequent dynamics of photoexcited states. For the herein studied tpphz bridged RuPt photocatalysts, on the one hand, the electronrich prbim ligands act as spectator ligands, i.e., allow unidirectional Ru-to-tpphz electron transfer upon photoexcitation between 400 and 470 nm, ultimately populating phzcentered states. However, on the other hand these MLCT phz transitions in turn decay back to the ground state instead of undergoing LMCT to the CAT, i.e., phz-to-Pt electron transfer -which is desired in the context of photocatalytic proton reduction. This is rationalized by TD-DFT simulations, showing that the 3 MLCT phz states are stabilized with respect to both, Pt-( 3 MCPt) and prbim centered states ( 3 MLCT prbim ) to such an extent, that subsequent phz-to-Pt electron transfer is prevented, e.g., as a result of high activation energy barriers. In consequence, (radiationless) deactivation is kinetically favored instead of the desired activation of the catalytic centre.