This manuscript describes the design, synthesis, characterization, and reactivity studies of organometallic Ni-III complexes of general structure TpNi(III)(R)(R-1) (Tp = tris(pyrazolyl)borate). With appropriate selection of the R and R-1 ligands, the complexes are stable at room temperature and can be characterized by cyclic voltammetry, EPR spectroscopy, and X-ray crystallography. Upon heating, many of these Ni-III compounds undergo C(sp(2))-C(sp(2)) or C(sp(3))-C(sp(2)) bond-forming reactions that are challenging at lower oxidation states of nickel.