Addition of 2,2'-bipyridine (bipy) to [Ni(NO)(bipy)][PF6] (1) results in formation of a rare five-coordinate nickel nitrosyl [Ni(NO)(bipy)(2)][PF6] (2). This complex exhibits a bent NO- ligand in the solid state. On standing in acetonitrile, 2 furnishes the NO coupled product, [Ni(kappa(2)-O2N2)(bipy)] (8) in moderate yield. Subsequent addition of 2 equiv of acetylacetone (H(acac)) to 8 results in formation of [Ni(acac)(2)(bipy)], N2O, and H2O. Preliminary mechanistic studies suggest that the N-N bond is formed via a bimetallic coupling reaction of two NO- ligands.