1 O 2 mediated synthesis of carbonyl substituted quinoline-2,4(1 H ,3 H )-diones in visible light: 4CzIPN as a reusable photocatalyst.

A mild and eco-friendly method for the construction of carbonyl-containing quinoline-2,4(1 H ,3 H )-diones has been developed in the presence of O 2 , photocatalyzed by reusable 4CzIPN in visible light. The method is transition-metal free, cost-effective, sustainable and gives the products in moderate to high yields.