Summary: S-g-C₃N₄ was synthesized via thermal polymerization of thiourea and characterized using FTIR and XRD. The photocatalyst exhibited 64.86% and 81.28% degradation of Brilliant Cresyl Blue and Malachite Green, respectively, under solar irradiation, following pseudo-first-order kinetics. Enhanced activity was attributed to sulfur doping, which improved charge separation and light absorption. The study presents a promising, eco-friendly approach for dye wastewater remediation, emphasizing the potential of S-g-C₃N₄ for large-scale environmental applications under natural sunlight.