The synthesis of 2,3‐dihydro‐4‐pyridones and 4‐quinolones was realized by visible‐light mediated photoredox‐catalyzed aerobic dehydrogenation of 4‐piperidones and 2,3‐dihydro‐4‐quinolones. This method enables the synthesis of cyclic enaminones in up to 89 % yield under mild and eco‐friendly conditions and with a high tolerance of functional groups using oxygen as an inexpensive terminal oxidant and rhodamine 6G as a readily available organic photocatalyst. The process can be extended to access 2,3‐dihydro‐4‐azocinones in up to 62 % yield via a [2+2] cycloaddition/ring‐expansion sequence in a telescoping one‐pot reaction. Hence, a protocol for the synthesis of three different types of N‐heterocycles was developed on the same general transformation.