<p>The industrial wastewater remains a major concern for researchers. Various advancements have been made to resolve this problem and photocatalysis is one of the most promising processes for wastewater treatment. In this regard, this work investigates the structural, magnetic, and optical properties of hydrothermally synthesized advanced CoFe₂O₄/SnO₂ heterojunction photocatalysts and their potential application in treating water contaminated with organic dye. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyzed the structural and morphological properties of the samples. X-ray Photoelectron Spectroscopy (XPS) was employed to investigate the electronic state of the elements in the nanocomposites. UV–Visible Diffuse Reflectance Spectroscopy (UV-DRS) showed that as the weight ratio of SnO₂ increases from 1 to 4, the effective bandgap increases from 2.87 to 3.26&#xa0;eV. This change may be attributed to new sub-bandgap energy levels generated after including a wide band gap semiconductor i.e. SnO₂ in CoFe₂O₄. CoFe₂O₄/SnO₂ (1:4) demonstrated a maximum photodegradation efficiency of 97% for rose bengal dye under UV lamp (300 W) irradiation in 90&#xa0;min. Furthermore, magnetic studies indicated that maximum magnetization is observed for CoFe₂O₄ and CoFe₂O₄/SnO₂ (1:1) showing maximum magnetization of 23.40&#xa0;emu/g among all synthesized nanocomposites. Thus, these magnetic nanocomposites can serves as promising materials for easily separable photocatalysts in industrial wastewater treatment.</p> Graphical Abstract <p></p>