NHC-Nickel(0) catalyzed 1,3-and 1,4diastereodivergent hydroacylative heteroenyne cyclization with aldehydes was achieved (Syn-:Anti-, switchable from up to 1:99 to 98:2). Both sets of heterocyclic diastereomers are accessible via this route, with a high γ-:α-enone structure ratio. Preliminary DFT investigations indicated that the manipulation of the N-substituent exerts a direct influence on the diastereoselectivity of NHC-nickelacyclopentene formation. The energy differences associated with the endocyclic bond angle (CÀ ZÀ C) changes noted in the calculations, might possibly account for the broad scope and high diastereodivergent selectivity observed.