Come to light: detailed analysis of thermally treated Phenyl modified Carbon Nitride Polymorphs for bright phosphors in lighting applications

•The polymerization scheme of phenyl modified Carbon Nitride is reported.•2D structure of phenyl modified g-C3N4 was achieved.•The phenyl group shift the optical properties of g-C3N4 in the visible region.•The phenyl-g-C3N4 polymer reach a quantum yield over 60% in the visible region.•A White LED based on the phenyl-g-C3N4 was tested in operating working conditions.