A visible-light-induced difunctionalization of alkenes with quinoxalin-2(1H)-ones and thioacids has been developed at room temperature. The present protocol, which utilizes 4CzIPN as the photocatalyst and K3PO4 as base, provides a series of structurally diverse thioester-containing quinoxalin-2(1H)-ones in moderate to good yields. This transformation undergoes through a radical pathway with the simultaneous installation of thioester and quinoxalin-2(1H)-one into one structural framework.