Here, we report our studies on the formation and reactions of oxetane and azetidine radicals using visible light mediated photoredox catalysis starting from carboxylic acid derivatives. We also report a systematic comparison of reaction outcomes for related substituted benzylic radicals and highlight important structural features for the reactivity of benzylic radicals. Most notably, we draw correlations between radical stability, hybridization and the equilibrium of the reversible Giese addition, which determines product yields and the extent of radical dimerization.