Based on our experimental findings and the relevant literature, we propose a mechanistic scenario outlined in Scheme 4E. Initially, the aryl bromide is activated through oxidative addition by low-valent nickel species (A), leading to the formation of an aryl-Ni II species (B). Subsequently, this complex undergoes transmetalation with the alkyl borane, resulting in the formation of species C. The excited state of the photocatalyst is reductively quenched, generating a high-valent Ni III species (D), which readily undergoes reductive elimination to yield the desired alkyl arene and Ni I species E. Finally, the reduced photocatalyst closes the catalytic cycle by reducing E back to A (E(PC/PCred) = -1.21 V vs SCE; 38 E(Ni I /Ni 0 ) > -1.1 vs SCE ).