The significant environmental impact of textile industries, particularly dye pollution from the textile effluents necessitates the urgent attention for its removal. Rhodamine B (RhB), known for its resistance to degradation which poses a considerable challenge. In this study, mesoporous gC3N4–ZnS QDs NCs were synthesized using an ultrasound-assisted co-precipitation method. Comprehensive characterizations, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy, and Brunauer-Emmett-Teller analysis were conducted to evaluate the materials. SEM images revealed a layered structure in the gC3N4 nanosheet, with small crystals clustered together, influencing the electronic and optical properties. The surface of gC3N4 was decorated with ZnS QDs to enhance the catalytic degradation of RhB. TEM analysis confirmed the uniform distribution of ZnS QDs over gC3N4 nanosheet. XRD and XPS analysis results before and after catalysis demonstrated the structural stability of the material. The degradation efficiency was achieved to be 97.8 % at a rate constant of 0.077 min−1 within 54 min. The stability and reusability of the NCs were confirmed through six consecutive cycles of catalytic degradation. The present study presents a promising strategy for the degradation of organic pollutants in aquatic ecosystems, offering insights for sustainable mitigation of textile dye pollution and paves a ways for manufacturing innovation.