A vast array of synthetic methods involving nickel catalysis has been developed in recent years. Methods that involve exogeneous reductants often are best accomplished with air-stable Ni(II) catalysts, which are desirable compared with more air-sensitive Ni(0) counterparts. While processes involving phosphine and pyridine ligand frameworks often perform well with Ni(II) precursors, 2 reactions that involve N-heterocyclic carbene ligands are more commonly performed with Ni(COD)2 as the precatalyst.