To probe for the possibility of thermal background reactivity in a self-sustained "dark cycle" promoted by reduction of Ni II by DABAl-Me3, we attempted the stoichiometric transmetalation of DABAl-Me3 to the nickel oxidative-addition complex 39 in the absence of photocatalyst and light (Scheme 4F i). This resulted in the formation of the cross-coupling product 40b in 58% yield. However, when employing 39 in catalytic amounts (Scheme 4F ii), only traces of the methylated arene 40b (<5% yield) could be detected. The majority of the aryl bromide 40a was left untouched (10% conversion). These observations point towards low-valent nickel intermediates, generated after a first transmetalation and reductive elimination, which engage in deleterious deactivation pathways rather than engaging in further catalytic reactivity via a two-electron pathway. When turning to photocatalytic conditions (Scheme 4F iii), a stark increase in yield was observed (85%). This result is consistent with the high yields obtained during the scope investigation and earlier control experiments, thereby underlining the necessity for both photocatalyst and light. These results taken together, suggest that if a thermal Ni 0 /Ni II or Ni I /Ni III catalytic cycle is operative, it is slow compared to the pathways that are enabled under photocatalytic conditions.