Dehydrohalogenation of pyridine-derived pincer ruthenium complexes often leads to dearomatized moieties, such as in Milstein’s PNN-Ru(CO)(Cl)(H) (1Py) catalyst. Thus, we were surprised to find an aromatized κ3-N,C,Pbinding mode in the lutidine-derived bidentate analogue [{LutP′}Ru(CO)(H)(PPh3)] (2), instead of a dearomatized compound, upon dehydrohalogenation of [{LutP}Ru(CO)(Cl)(H)(PPh3)] (1). The reaction of 2with H2results in the formation of the cis-dihydride [{LutP}Ru(CO)(H)2(PPh3)] (3), and labeling studies confirm cooperative metal–ligand activation. 3exhibits reversible photoisomerization, forming another cis-dihydride isomer (4) upon irradiation. The lability of 4toward ligand substitution was leveraged to demonstrate photoenhanced H2production via acceptorless alcohol dehydrogenation. Labeling studies implicate metal–ligand cooperative (MLC) processes during the photocatalytic reaction, but they appear to be off-path processes on the basis of our mechanistic study of the system. The latter emphasizes that aromatization/dearomatization may not be necessary for acceptorless transformations, which is generally consistent with several contemporary studies on analogous Ru catalysts.