An extensive range of functionalized aliphatic ketones with good functional-group tolerance has been prepared by a Ni^I-promoted coupling of either primary or secondary alkyl iodides with NN₂ pincer Ni^II-acyl complexes. The latter were easily accessed from the corresponding Ni^II-alkyl complexes with stoichiometric CO. This Ni-mediated carbonylative coupling is adaptable to late-stage carbon isotope labeling, as illustrated by the preparation of isotopically labelled pharmaceuticals. Preliminary investigations suggest the intermediacy of carbon-centered radicals.