Indole-fused medium-sized diazepinones are privileged structural motifs found in many high-value pharmaceuticals. To construct these challenging molecular skeletons, previous methods are mainly achieved by [5+2] annulation strategies with the aid of transition metal (Pd, Rh, Ru) catalyzed oxidative C-H coupling. Herein, we report a novel visible-light-induced sulfonylation-cyclization-selenylation reaction for the rapid construction of highly functionalized indole-fused medium-sized diazepinones with biomass feedstock 2-Me-THF as the medium. Based on the mechanism studied, an electrophilic radical sulfonylation-cyclization and subsequent aerobic electrophilic C-3 selenylation route is proposed.