The meta-terphenyl diphosphine, m-P2, 1, was utilized to support Ni centers in the oxidation states 0, I, and II. A series of complexes bearing different substituents or ligands at Ni was prepared to investigate the dependence of metal–arene interactions on oxidation state and substitution at the metal center. Complex (m-P2)Ni (2) shows strong Ni0–arene interactions involving the central arene ring of the terphenyl ligand both in solution and the solid state. These interactions are significantly less pronounced in Ni0 complexes bearing L-type ligands (2-L: L=CH3CN, CO, Ph2CN2), NiIX complexes (3-X: X=Cl, BF4, N3, N3B(C6F5)3), and [(m-P2)NiIICl2] (4). Complex 2 reacts with substrates, such as diphenyldiazoalkane, sulfur ylides (Ph2SCH2), organoazides (RN3: R=para-C6H4OMe, para-C6H4CF3, 1-adamantyl), and N2O with the locus of observed reactivity dependent on the nature of the substrate. These reactions led to isolation of an η1-diphenyldiazoalkane adduct (2-Ph2CN2), methylidene insertion into a NiP bond followed by rearrangement of a nickel-bound phosphorus ylide (5) to a benzylphosphine (6), Staudinger oxidation of the phosphine arms, and metal-mediated nitrene insertion into an arene CH bond of 1, all derived from the same compound (2). Hydrogen-atom abstraction from a NiI–amide (9) and the resulting nitrene transfer supports the viability of Ni–imide intermediates in the reaction of 1 with 1-azido-arenes.