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Ruthenium polypyridyl complexes have gained significant interest as photochemotherapies (PCTs) where their excited-state properties play a critical role in the photo-cytotoxicity mechanism and efficacy. Herein we report a systematic electrochemical, spectrochemical, and photophysical analysis of a series of ruthenium( ii ) polypyridyl complexes of the type [Ru(bpy) 2 (N–N)] 2+ (where bpy = 2,2′-bipyridine; N–N is a bidentate polypyridyl ligand) designed to mimic PCTs. In this series, the N–N ligand was modified through increased conjugation and/or incorporation of electronegative heteroatoms to shift the metal-to-ligand charge-transfer (MLCT) absorptions near the therapeutic window for PCTs (600–1100 nm) while incorporating steric bulk to trigger photoinduced ligand dissociation. The lowest energy MLCT absorptions were red-shifted from λ max = 454 nm to 564 nm, with emission energies decreasing from λ max = 620 nm to 850 nm. Photoinduced ligand ejection and temperature-dependent emission studies revealed an important interplay between red-shifting MLCT absorptions and accessing the dissociative 3 dd* states, with energy barriers between the 3 MLCT* and 3 dd* states ranging from 850 cm −1 to 2580 cm −1 for the complexes measured. This work demonstrates the importance of understanding both the MLCT manifold and 3 dd* state energy levels in the future design of ligands and complexes for PCT.