A new method for the direct carboxylation of unactivated secondary alkyl bromides has been developed using a combination of photoredox and nickel catalysis. This approach enables site-selective insertion of CO₂ at the initial C(sp³)-Br bond, avoiding undesired β-hydride elimination and chain-walking processes. The reaction is highly selective, with excellent chemo- and site-selectivity, and operates under mild conditions. The mechanism involves the formation of Ni(I)-alkyl species, which facilitates CO₂ insertion at the desired site. The study also highlights the importance of ligand effects in controlling reactivity and selectivity. The method was tested with a wide range of substrates, including those with branched or aromatic substituents, and showed high efficiency and selectivity. The reaction was further supported by theoretical calculations, which revealed the low energy barrier for CO₂ insertion and the role of photoredox processes in electron transfer. The study also explored the influence of different ligands on the reaction outcome, demonstrating that the ligand backbone plays a crucial role in minimizing side reactions. The results demonstrate the potential of this method for the efficient synthesis of carboxylic acids from unactivated secondary alkyl bromides.A new method for the direct carboxylation of unactivated secondary alkyl bromides has been developed using a combination of photoredox and nickel catalysis. This approach enables site-selective insertion of CO₂ at the initial C(sp³)-Br bond, avoiding undesired β-hydride elimination and chain-walking processes. The reaction is highly selective, with excellent chemo- and site-selectivity, and operates under mild conditions. The mechanism involves the formation of Ni(I)-alkyl species, which facilitates CO₂ insertion at the desired site. The study also highlights the importance of ligand effects in controlling reactivity and selectivity. The method was tested with a wide range of substrates, including those with branched or aromatic substituents, and showed high efficiency and selectivity. The reaction was further supported by theoretical calculations, which revealed the low energy barrier for CO₂ insertion and the role of photoredox processes in electron transfer. The study also explored the influence of different ligands on the reaction outcome, demonstrating that the ligand backbone plays a crucial role in minimizing side reactions. The results demonstrate the potential of this method for the efficient synthesis of carboxylic acids from unactivated secondary alkyl bromides.