Ni-catalyzed cross-electrophile coupling (CEC) reactions to generate new C(sp 2 )-C(sp bonds have received significant attention over the last decade due to the prevalence of these linkages in natural products and pharmaceuticals, and the limitations of current synthetic methods to form these bonds (Figure ). Despite the widespread interest, reaction development has relied heavily on the empirical screening of reaction parameters, such as the identity of the ancillary ligand and presence of pyridine and alkali halide additives. Consequently, reaction conditions developed using this strategy are often specific to a limited range of substrates. For example, typical reaction conditions for the coupling of aryl halides with primary alkyl bromides, primary alkyl iodides, or primary benzyl chlorides utilize different ligand sets, additives, solvents, and reductants. Further, even within a particular substrate class, for instance nitrogencontaining heteroaryl halides, significant changes are often required depending on the exact identity of the substrates. Unfortunately, it is often unclear why a given alteration of reaction conditions or the presence of an additive results in the desired reactivity, which complicates the translation of the method to other substrates. These challenges have limited the application of CEC in synthetic chemistry, especially for the functionalization of complex pharmaceutically relevant substrates. A potential reason for the lack of generalizable conditions for CEC is related to the proposed mechanism, in which it is difficult to independently control key on-and off-cycle reactions (Figure ). Specifically, in CEC reactions between aryl and alkyl halides, complexes of the type LNi II (Ar)X (X = Cl, Br, or I) are proposed to be crucial intermediates, as they are both the catalyst resting state and responsible for capturing free alkyl radicals (Figure ). In an ideal CEC reaction, the LNi II (Ar)X intermediate would be stable and the rate at which radicals are generated would be controlled relative to the concentration of LNi II (Ar)X to facilitate effective radical capture (Figure ). However, the rate of alkyl radical generation by a Ni I halide intermediate cannot be tuned separately from the concentration of LNi II (Ar)X because both complexes are intermediates on the same catalytic cycle. Additionally, under the reaction conditions typically utilized, LNi II (Ar)X complexes are unstable and can undergo two deleterious side reactions: (i) bimolecular decomposition to produce biaryl, which is especially problematic when high catalyst loadings are employed, or (ii) direct reduction to produce protodehalogenated and biaryl products, which can readily occur when using strong heterogeneous Zn 0 or Mn 0 reductants. Further, heterogeneous reductants present practical limitations, including challenges with process scale reactions, flow chemistry, and automated chemical synthesis, and typically require the use of toxic amide-based solvents and additives for efficient electron transfer to solution state catalysts. We hypothesized that by addressing the challenges related to the stability of the LNi II (Ar)X intermediate and the inability to discretely control radical generation we could develop a general and practical system for C(sp 2 )-C(sp 3 ) CEC (Figure ).