A visible-light-promoted formal [2 ​+ ​2 + 1] cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed. The protocol features operational simplicity, mild reaction conditions with blue LED light employing Ru(bpy)3Cl2.6H2O as a photoredox catalyst, a combination of O2 from air and Cu(OAc)2 as the oxidant and broad substrate applicability.