<p>Nickel-catalysed cross-coupling reactions have emerged as a powerful strategy to construct complex molecules. Such reactions generally employ Ni(II) or Ni(0) compounds as precatalysts. Although highly desirable, catalytically competent Ni(I) sources with exchangeable ancillary ligands are lacking. Here we report the synthesis, characterization and catalytic activity of thermally stable dinuclear Ni(I) complexes supported by commercially available isocyanides as a general solution to this problem. Two classes of Ni(I) isocyanide complexes have been developed: coordinatively saturated homoleptic compounds and coordinatively unsaturated Ni(I)-halide compounds. These Ni(I) compounds exhibit rapid ligand substitution and are efficient catalysts in Kumada, Suzuki–Miyaura and Buchwald–Hartwig cross-coupling reactions, suggesting their potential use as either Ni(I) catalysts or precatalysts. In addition, bromide-selective functionalization of polyhalogenated arenes with Grignard reagents is achieved under nickel catalysis. Finally, spectroscopic and mechanistic studies are performed to establish the general use of isocyanides as spectator ligands for cross-coupling reactions, representing an untapped chemical space for reaction discovery.</p><p></p>