No reaction occurred in the dark either at room temperature or at 65 o C (Table , entries 2-3) confirming the essential role of light excitation in mediating the reaction. Similarly, no product was observed in the absence of the photo-or nickel-catalyst (Table , entries 4-5). Only trace amounts of the product were obtained when the reaction was carried out without added dtbbpy ligand (Table , entry 6). Several nickel catalysts were tried to replace NiBr2(dtbbpy), but the product yield did not improve (Table ). Upon further optimization, we found that the presence of a catalytic amount of a weakly basic additive, such as K2HPO4 accelerates the reaction and increases the product yield (Table , entry 7). A possible effect of the added base may be the neutralization of formed HBr keeping the Br -anion concentration sufficiently high for the photooxidation. Inorganic bases gave better results compared to organic base additives (Table ). The screening of different photocatalyts and solvents gave the best product yield using Ir{dF(CF3)ppy}2(dtbpy)]PF6 in ethyl acetate as a solvent (Table , S5).