A light-promoted Ni-catalyzed cyanation of aryl halides employing 1,4-dicyanobenzene as a cyanating agent is reported. A broad array of aryl bromides, chlorides, and druglike molecules could be converted into their corresponding nitriles (65 examples). Mechanistic studies suggest that upon irradiation, the oxidative addition product Ni(II)(dtbbpy)(p-C6H4CN)(CN) undergoes homolytic cleavage of the Ni-aryl bond to generate an aryl radical and a Ni(I)-CN species, the latter of which initiates subsequent cyanation reactions.