Abstract <p>The SrSO₄/g-C₃N₄ heterostructure was prepared using various g-C₃N₄ concentrations (10, 20, 30, and 40%) via the sonochemical method. The SrSO₄(SO) and g-C₃N₄ (CN) exhibited an orthorhombic crystal structure and stacking of aromatic rings, respectively. The SEM reveals that SO and CN exhibited the micro-sized discocyte and transparent layered morphology, respectively. The incorporation of CN into the SO significantly reduces the bandgap and charge carrier recombination, which effectively enhances the light harvesting and charge carrier lifetime properties. Among the as-prepared catalysts, SOCN-3 exhibited higher MB and MO removal efficiency of 89 and 75%. The modified Langmuir–Hinshelwood equation adopted for the analysis of reaction kinetics and SOCN exhibited a pseudo-first-order model. Furthermore, the morphological variations were analysed after the experiment, which indicated that SOCN was highly stable after the 5 cycles. The improved photocatalytic activity is mainly attributed to the synergistic interaction between SO and CN, which enhances electron–hole separation and generation of reactive species.</p> Novelty statement <p>This study discusses the novel SrSO₄/g-C₃N₄ (SOCN) heterostructure preparation for photocatalytic degradation of organic pollutants. The integration of SrSO₄ with g-C₃N₄ promotes efficient charge separation and suppresses rapid electron–hole recombination. The formation of this heterojunction enables improved light utilization and reactive species generation under irradiation. This work provides a novel approach to the design of stable, non-toxic, and reasonably priced heterostructured materials for effective wastewater treatment applications.</p> Graphical abstract <p></p>