Nowadays many textile industries release their waste products directly into water resources like lakes, rivers and ground water has become a serious problem. These dye pollutants are difficult to remove by conventional methods like adsorption, filtration, coagulation etc. Hence, there is a need to develop more appropriate and inexpensive methods of industrial effluent treatment. In this work, we report a green route for the synthesis of nickel hydroxide nanoparticles (Ni(OH)(2)NPs) using an aqueous fruit extract of star anise (Illiciumverum) under optimized hydrothermal conditions. The morphology, crystalline structure, chemical composition, and catalytic activity of the synthesized Ni(OH)(2)NPs were evaluated using FTIR, XRD, XPS, HR-TEM, SAED and SEM-EDX. The XRD results and HR-TEM images revealed that the Ni(OH)(2)NPs have mixed morphologies including spherical, hexagonal, and rod shapes with average particle size of similar to 16.1 nm and consist of the beta-phase. The obtained Ni(OH)(2)NPs were proven to be efficient catalyst which improved the reduction rates of the rhodamine B and rhodamine 6G (RhB and Rh6G) dyes.