The properties and reactivity of metal complex photocatalysts for solar-to-fuel conversion can be conveniently controlled by the molecular design of their ligands. In this work, rhenium(I) tricarbonyl polypyridyl compounds, fac-[Re(NN)(CO)₃Cl], where NN is a 1,10-phenanthroline ligand having pyrrole (Re-pyr), indole (Re-ind), or carbazole (Re-cbz) groups attached to its 4 and 7 positions, were investigated as photocatalysts for reducing CO₂ to CO. These complexes can harvest light in the visible region and displayed an exceptionally high photocatalytic performance, with an up to 10-fold increase in the TON_CO values compared to the unsubstituted Re-phen parental complex. Re-pyr was the best performing photocatalyst in this series, with a TON_CO of 125 after 24 h and Φ_CO = 0.22. The TON_CO of Re-pyr, Re-ind, and Re-cbz surpassed even the most efficient Lehn-type photocatalysts reported to date to promote the photoreduction of CO₂ using triethanolamine as the sacrificial electron donor, without a second molecule working as a light absorber. The excellent photocatalytic performance of this series was intimately related to the presence of N-heterocyclic substituents, which enhanced the visible-light absorption properties of the compounds, favored the kinetics and thermodynamics of each individual step of the photocatalysis, inhibited deactivation of the photocatalysts by dimerization, stabilized reduced intermediates, and unlocked an alternative CO₂ photoreduction pathway that proceeds predominantly through a two-electron reduced species [Re(NN)(CO)₃]⁻.