Herein, we report a cross-electrophile coupling of benzonitrile derivatives and aryl halides with a simple cobalt-based catalytic system under mild conditions to form biaryl compounds. Even though the cobalt catalyst is able to activate the C(sp 2 )-CN bond alone, the use of the AlMe3 Lewis acid enhances the reactivity of benzonitriles and improves the cross-selectivity with barely any influence on the functional group compatibility. X-Ray structure determination of an original low-valent cobalt species combined with catalytic and stoichiometric reactions reveal a catalytically active cobalt(I) species towards the aryl halide partner. On the other hand, experimental insights, including cyclic voltammetry experiments, suggest the involvement of a cobalt complex of a lower oxidation state to activate the benzonitrile derivative. Finally, DFT calculations support the proposed mechanistic cycle involving two low-valent cobalt species of different oxidation states to perform the reaction.

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