ZnO nano particles and Cu modified ZnO nano composites have been prepared by simple, facile hydrothermal approach. The novelty of this work was the use of aqueous methanolic solution (50:50 ratio) as the solvent of reaction, while zinc chloride was used as the precursor of ZnO NPs and Cu- modified ZnO nano composites. XRD results revealed that the synthesized ZnO and Cu-modified ZnO nano composites were of nano size and XRD patterns matched with JCPDS Card 35-1451, confirming the synthesis of ZnO nanoparticles. The FT-IR results confirmed the synthesis of target materials and also the adsorption of Cu metal on ZnO surface. The UV visible spectroscopic analysis indicated that the optical properties improved as the concentration of Cu metal increased on ZnO surface. SEM analysis explored the spherical shape of synthesized nano composites. The EDX graph showed the elemental composition of prepared materials that composed of Zn, O and Cu and no other impurity was found. The Tartrazine Yellow Azo Dye was degraded to investigate the photo catalytic activity which was optimized under sunlight with increasing the Cu metal concentration on surface of ZnO. Manuscript profile