<p>Five ruthenium complexes of 4-aminoantipyrine based Schiff base derivatives were synthesized and duly characterized by FT-IR, UV–Vis, and ESI-Mass spectroscopic analyses. The catalytic performance of the complexes towards the degradation of methylene blue (MB) was studied in aqueous medium using H₂O₂ as an oxidant. The reaction parameters, including the catalyst loading, concentration of H₂O₂, pH, reaction temperature, and initial dye concentration, were systematically optimized. The ruthenium complex of the 4-aminoantipyrine ligand achieved a dye degradation efficiency of 95.38% within 30&#xa0;min. The catalyst stability and recyclability were examined for four consecutive degradation cycles. The effect of dissolved salts on the degradation efficiency was investigated by introducing salts such as NaCl, Na₂SO₄, KBr, and K₂SO_4. From the kinetic studies, the MB degradation was found to follow pseudo-second order kinetics with a rate constant of 0.058&#xa0;g&#xa0;mg⁻¹&#xa0;min⁻¹. The remarkable catalytic activity of the system, along with facile synthesis under mild conditions, reflects the strong potential of the catalyst for the removal of toxic MB dye from wastewater.</p> Graphical abstract <p></p>