Bimetallic (Et4N)(2)[Co-2(L)(2)], (Et4N)(2)[1] (where (L)(3-) = (N(o-PhNC(O)Pr-i)(2))(3-)) reacts with 2 equiv of O-2 to form the monometallic species (Et4N)-[Co(L)O-2], (Et4N)[3]. A crystallographically characterized analog (Et4N)(2)[Co(L)CN], (Et4N)(2)[2], gives insight into the structure of [3](1-). Magnetic measurements indicate [2](2-) to be an unusual high-spin Co-II-cyano species (S = 3/2), while IR, EXAFS, and EPR spectroscopies indicate [3](1-) to be an end-on superoxide complex with an S = 1/2 ground state. By X-ray spectroscopy and calculations, [3](1-) features a high-spin Coll center; the net S = 1/2 spin state arises after the Co electrons couple to both the O-2(center dot-) and the aminyl radical on redox non innocent (L-center dot)(2-). Dianion [1](2-) shows both nucleophilic and electrophilic catalytic reactivity upon activation of O-2 due to the presence of both a high-energy, filled O-2(-) pi* orbital and an empty low-lying O-2(-) pi* orbital in [3](1-).