The increasing discharge of synthetic dyes from textile effluents poses a serious threat to aquatic ecosystem and human health. Conventional wastewater treatment methods such as adsorption, coagulation and biological processess are often limited by secondry pollution and incomplete dye removal. Heterogenuous photocatalysis has emerged as a sustainable and effficient alternative for degrading persistent organic pollution under light irradiation. In this study, pure and Nickel doped Bismuth Oxide (2&4% Ni-Bi2O3) nanoparticles were synthesized via a simple precipitation method and evaluated for their photocatalytic performance. The prepared nanoparticles wer characterized using various advance techniues to understand the structure and activity of the catalyst. The photocatalytic efficiency was assessed for the degradation of Malachite Green (MG) and Methyle Blue (MB) dyes under visible light. Among all the catalyst , 4% Ni- Bi2O3 exhibited the highest degradation effiecieny, achieving 98% removal of MG and 78.98% of MB under optimized reaction condition (3 mg catalyst dosage, 20 µM MG/ 18µM MB concentration, pH 9). Kinetic analysis confirmed the psudo-first-order behavior. Overall, the study demonstrates that Nickel doeped bismuth oxide nanoparticles are effective photocatalyst for dye degradatio, highlighting theor potential aas an eco-friendly strategy for wastewater treatmetnt and reuse.