An efficient and practical synthesis of benzothiazine by visible-light-mediated free radical reaction has been developed. This protocol provides a new, facile, eco-friendly strategy to construct benzothiazine and quinoxaline derivatives via formation of C-S and C-N bonds under metal-free condition. This synthesis has been performed under visible light illumination in aqueous ethanol at room temperature using aromatic aldehyde, o-aminothiophenol and isocyanide as reactants. [GRAPHICS] .