Resonance Raman (RR) spectroscopic studies, supplemented by excited state absorption techniques, were used to probe the effect of modifications to the electronic environment on the excited states of mono- and di-nuclear Ru(II) polypyridyl complexes containing triazole-based bridging ligands. Ground state RR spectroscopy showed that coordination of the sigma-donating bridging ligands to a second Ru(bpy)(2) moiety resulted in stabilization of the metal d(pi)-orbitals, whereas excited state RR spectroscopy revealed a concomitant stabilization of the pi*-level of the bridging ligand. With 3,5-bis(pyrazin-2-yl)-1,2,4-triazole) as bridging ligand (BL), the latter effect was sufficient to cause a switching from a bpy-based to a BL-based (MLCT)-M-3 state, with evidence suggesting charge polarisation towards a pyrazine fragment. Further, for pyrazine-containing bridging ligands, protonation of the triazole fragment resulted in a switching of the lowest excited state to a BL-based excited state. (C) 1998 Elsevier Science S.A.