We explored the possibility of a β-chloroacylation of alkenes using readily available, unactivated 1-phenylbutene (A1), benzoyl chloride (B1), in the presence of catalytic amounts of various homo-and heteroleptic Cu(I) complexes under irradiation with a blue light-emitting-diode (LED) (Fig. , for more details, see Supplementary Tables ). After extensive optimization, several critical reaction parameters were recognized: Employing THF as the solvent at a concentration of 0.0625 M is essential for the success of the reaction. Using homoleptic Cu(I) complexes [Cu(dap)2]Cl and [Cu(dmp)2]Cl resulted in no product formation, most likely due to their insufficient excited-state lifetimes. Moving to heteroleptic Cu(I) complexes, Cu(dmp)(BINAP)BF4 gave rise to the desired product 1 in 76% yield, while other Cu(I) heteroleptic complexes such as Cu(dmp)(Xanphos)BF4 and Cu(phen)(Xanphos)BF4 were vastly inferior (7-12% yield), which is again in agreement with their much shorter excited-state lifetime values. The presence of base (Na2CO3) negatively impacted the efficiency of the reaction. Control experiments confirmed the necessity for light and the Cu(I) catalyst. Further, an inert atmosphere is essential for this reaction; only trace amounts of product were generated when the reaction was performed in air. When styrene A2, as an example of an activated alkene, was employed, the desired product 2 was obtained in near-quantitative yield under the standard reaction conditions, being superior to other variations tried. The protocol developed here operates at room temperature and does not require base and additional oxidants or reductants.