The degradation of dyes and colors from textile contaminants has been a major source of concern owing to issues with visibility, health, and toxicity. Therefore, the dye must be treated before being released into the environment. Co-precipitation was employed to synthesis pristine and Co (0.01 M, 0.03 M, and 0.05 M) doped NiMnO3 catalysts for the purpose of this study. Analytical methods such as X-ray diffraction, fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy were utilized in the process of characterizing of the synthesized catalysts. The band gap of NiMnO3 (3.0 eV) has been confirmed from UV-Vis. spectra and doping has also been shown to cause a reduction in the band gap. In the XRD spectrum, a peak (110) at 36° has confirmed the rhombohedral crystal structure of NiMnO3. Both intense peaks on 504 and 635 cm−1 in the FTIR spectra also confirmed the functional present in NiMnO3. These synthesized catalysts were employed for the photocatalytic breakdown of the synthetic dye methylene violet. The highest degradation of methylene violet was obtained by using Co (0.05 M) doped NiMnO3 (91.9%). Three cycles of recycling showed a modest drop in dye degradation from 91.8% to 90%, indicating the great stability of the catalyst. The major species taking part in photo-catalysis were found to be h+ and .O2- by using IPA, BQ and 2NA-EDTA scavenger. The above results show that Co (0.05) doped NiMnO3 can be the suitable photocatalyst for the photocatalytic breakdown of methylene violet and it can be also used in different energy storage applications.