<p>Developing cost-effective and eco-friendly nanomaterials for multifunctional applications is crucial for advancing sustainable energy storage and environmental remediation technologies. We explore the green synthesis of Co_xBiF_1-xO₃ (0 ≤ x ≤ 0.15) using Moringa oleifera plant extract, emphasizing their structural, electrochemical, and photocatalytic properties. XRD analysis confirmed the perovskite structure with R3C space group of synthesized nanoparticles. Raman and FTIR analysis validated the structural integrity and vibrational characteristics of the synthesized nanomaterials. SEM analysis revealed a reduction in grain size and increased density of nanostructures upon doping, while TEM images confirmed irregular morphology and further reduction in particle size for Co-doped samples. The optical properties investigated using UV-Vis spectroscopy and the optical bandgap decreased from 2.70 eV to 2.55 eV with increasing concentration of Co. Electrochemical characterization revealed a significant improvement in specific capacitance up to 501 F/g. 15% Co-doped BiFeO₃ displayed exceptional capacitance retention of 87% after 5000 cycles. The photocatalytic efficiency under solar irradiation showed that Co doping significantly increased the methylene blue degradation. Cost-effective and sustainable synthesis route for multifunctional BiFeO₃ based materials, promising candidate for energy storage applications and environmental remediation.</p> Graphical Abstract <p></p>