Conversely, when cyclopropylmethyl redox-active ester 15 was reacted with bismuthinidene 1, a complex analogous to 14 was not observed. Instead, radical ring-opening product 17 was immediately obtained, even in the dark. This is consistent with the two distinct mechanistic scenarios for the oxidative addition. On one hand, polar SN2-type reaction of cyclopropylmethyl iodide with 1 initially leads to 14, which eventually ring-opens via radical equilibrium. On the other hand, SET and fragmentation of RAE 15 leads to an incage bismuth(II)/alkyl radical pair (18), for which cyclopropane ring-opening is faster than radical recombination, resulting in the formation of 17 (Fig. ). The radical-equilibrium hypothesis is consistent with the reactivity displayed by these complexes: the secondary alkyl radical derived from 13 reacts with Michael acceptors such as phenylvinylsulfone giving Giese addition product 21, either in the dark (57%) or under blue-light irradiation (85%) (Fig. ). The alkyl-radical fragment of several complexes was successfully trapped with TEMPO leading to C(sp 3 )-OTEMP adducts. Moreover, we observed that catalytic amounts of 1 can promote Giese-type reactions, among others, upon blue light irradiation (for these catalytic examples, and for TEMPO trapping experiments, see Supplementary Information). Interestingly, when attempting the isolation of α-amino alkyl-bismuth(III) adduct 23 derived from proline, we observed the exclusive formation of the product of decarboxylative amination 24, with recovery of bismuthinidene 1 (Fig. , right). It was speculated that product 24 would arise from the oxidation of the corresponding α-amino alkyl radical by a highly reactive bismuth(II) species. This would lead to the formation of an electrophilic iminium ion, which ultimately reacts with the tetrachlorophthalimide (TCNPhth) anion to forge the C-N bond (for details, see Fig. and Supplementary Information). At this point, it was envisaged that this reactivity could be exploited to engage the corresponding iminium with external N-nucleophiles, leading to a formal C-N cross-coupling reaction. After optimization of the conditions, we found that the reaction of RAE 22 with 3 equivalents of benzimidazole (25) in the presence of 10 mol% of 1 in DMA at 25 °C afforded the product of C-N cross coupling (26) in 88% yield within 2 h (Fig. ). Under these conditions, the only observed side products were 24 (nucleophilic competition by TCPhth) and the expected amide bond-formation product 27, which could be minimized by controlling the stoichiometry and selecting the appropriate solvent (Fig. , entry 1 vs 3), respectively (see Supplementary Information for optimization details). Control experiments without Bi catalyst led exclusively to acyltransfer product (entry 2). The high efficiency of the optimized reaction relies on the faster kinetics of the Bi-radical process compared to the background amide formation. For example, the reaction could be carried out at -30 °C in DMF (entry 4), or at room temperature in DMA in only 10 min (entry 5), giving the desired product in 56% and 85% yield, respectively. To exclude completely the requirement of photoexcitation for any of the steps of the transformation to proceed, the reaction was carried out under exclusion of ambient light, giving comparative results (entry 6). Finally, we found that addition of TEMPO completely inhibits the reaction, presumably due to the inertness of the formed bismuth-TEMPO adduct (entry 7). The scope of the transformation is presented in Fig. . RAEs of readily available natural and non-natural α-amino acids were interrogated (either fully protected, or with free N-H bonds) as electrophilic partners.