The degradation of methyl orange (MO) as an anionic dye was evaluated with the aid of bismuth ferrite (BiFeO3) impregnated regenerated cellulo se (RC) nanocomposite film as a photocatalyst. Microcrystalline cellulose (MCC) was used to obtain the RC films using the solution casting method, wherein BiFeO3 (0�5 wt) was added into the MCC dissolution ionic liquid 1-butyl-3-methylimidazolium chloride system. The film characterization was accomplished by Fourier transform infrared spectroscopy, XRD, X-ray photoelectron spectroscopy, UV�visible diffuse reflectance spectroscopy, Brunauer�Emmett�Teller surface area, TGA, SEM and vibrational sample magnetometry. The photocatalytic performance of the film was evaluated by treating the catalyst dye mixture under direct sunlight until significant colour removal of the dye was observed. The concentration of the dye at each time interval was determined with the aid of UV�visible spectroscopy. According to the findings about characterization, BiFeO3 showed good compatibility with RC, and the impregnation of BiFeO3 in RC did not alter the physicochemical properties of pure RC. The photocatalyst showed a 90 degradation of 10 ppm MO as maximum with 3 wt BiFeO3 loading at pH 2 and the catalytic performance was stabilized for four cycles. © 2023 Society of Industrial Chemistry. © 2023 Society of Industrial Chemistry.