Excited state vibrational spectroscopy of metal complexes of dipyrido[3,2-a:2′,3′-c]phenazine

► The electronic structure of dipyrido[3,2-a:2′,3′-c]phenazine complexes is influenced by the presence of two close lying MOs (b1(ψ) and b1(phz)). ► Complexes have both MLCT and IL states that lie close in energy. ► Assignment of these states may be determined through time-resolved resonance Raman or infrared measurements. ► Time-resolved infrared measurements provide less ambiguous data for complexes with {Re(CO)3(R)}+ than Raman. ► Ultrafast time-resolved infrared measurements reveal relaxation between MLCT and IL states that are dependent on substituents.