The discovered photocatalytic reaction does not require the C-H partner to be a solvent and can proceed efficiently with a few equivalents of substrates. For example, 3 equivalents of 1,3-benzodioxole afforded 3e at an isolated yield of 82% using 1,4-dioxane as the solvent (Method B in Figure ). The reaction with tetrahydrothiophene also proceeded smoothly, affording 3f in an excellent yield of 99%. Various acyclic (3g -3i) and cyclic (3j) amide substrates also yielded the corresponding addition products at 70%-98% isolated yields using Method A or B. The reaction protocol was easily adapted to activate benzylic C-H bonds, producing 3k, 3l, and 3m at good to excellent yields of 47% to 87%. Similar experiments were carried out using other electrondeficient alkenes, including unsaturated ketones such as chalcones (3A-3C) and vinyl pyridine (3D), resulting in good to excellent yields (37% -83%).