This Article describes the synthesis and characterization of cyclometalated aminoquinoline Ni-II sigma-aryl and sigma-alkyl complexes that have been proposed as key intermediates in Ni-catalyzed C-H functionalization reactions. These Ni-II complexes serve as competent catalysts for the C-H functionalization of aminoquinoline derivatives with I-2. They also react stoichiometrically with I-2 to form either aryl iodides or beta-lactams within minutes at room temperature. Furthermore, they react with Ag-I salts at -30 degrees C to afford isolable five-coordinate Ni-III species. The Ni-II sigma-aryl complexes proved inert toward C(sp(2))-I bond-forming reductive elimination under all conditions examined (up to 140 degrees C in DMF). In contrast, a Ni-III sigma-alkyl analogue underwent C(sp(3))-N bond-forming reductive elimination at 140 degrees C in DMF to afford a beta-lactam product. However, despite the ability of this latter Ni-III species to participate in stoichiometric product formation, the complex was not a competent catalyst for beta-lactam formation. Overall, these results suggest against the intermediacy of Ni-III species in these C-H functionalization reactions.