In this investigation, copper oxide (CuO), cobalt oxide (Co3O4) and bimetallic copper oxide-cobalt oxide (CuO-Co3O4) nanoparticles were synthesized using an aqueous extract of Wrightia tinctoria leaves and characterized through UV-Vis, FT-IR, XRD, TEM and zeta potential analyses. The FT-IR analysis identified that specific phytoconstituents are responsible for the reduction and capping agents in nanoparticle synthesis. TEM analysis determined size and shape and zeta potential analysis assessed stability. The CuO and Co3O4 NPs, synthesized through an eco-friendly approach, were employed for 4-nitrophenol reduction with sodium borohydride. The reaction rate, was computed at 1 × 10-4 s-1, which indicated the pseudo-first-order kinetics. The synthesis of 4-aminophenol was also successfully acheived demonstrated that the excellent catalytic activity of CuO, Co3O4 and CuO-Co3O4 nanoparticles as catalysts.