Oxygen reduction is a critical half reaction in renewable fuel cell development and a key step in the development of aerobic oxidation reactions. Herein, we report rapid two-electron O-2 reduction by a d(0) Zr-IV center with an appended redox-active Co-I site serving as an electron reservoir. The early/late heterobimetallic Zr/Co complex (THF)Zr(MesNP(i)Pr(2))(3)(CoCNBu)-Bu-t (1) reacts readily with O-2 and O atom transfer reagents to generate reactive oxygenated species including terminal peroxo and oxo complexes, (O-2)Zr(MesNP(i)Pr(2))(3)(CoCNBu)-Bu-t (2) and O Zr(MesNP(i)Pr(2))(3)(CoCNBu)-Bu-t (3). The bimetallic Zr/Co complex provides a new cooperative synthetic pathway to promote multielectron redox processes such as oxygen reduction, with each metal playing a distinct role as a substrate binding site or redox mediator.