A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employing 4CzIPN as the metal-free photocatalyst and dioxygen (air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with favorable functional group tolerance. Radical trapping experiment and fluorescence quenching experiments were performed to elucidate this visible-light mediated radical reaction process. A mild and efficient photochemical multi-component reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids was established for the synthesis of sulfonated quinoxalin-2(1H)-ones. This multi-component could be carried out at room temperature by employing 4CzIPN as the photocatalyst and dioxygen (air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were conveniently obtained in satisfactory yields. Display omitted