Abstract Copper(II) oxide (CuO) nanoparticles have been found to be an efficient catalyst for 1,3-dipolar cycloaddition (CuAAC) of aromatic azides and acetylenic xanthenes furnishing the corresponding xanthene substituted triazoles in excellent yields. CuO nanoparticles have been synthesized from copper acetate by simple co-precipitation method and characterized by scanning electron microscope, energy dispersive X-ray analysis, transmission electron microscope, and X-ray diffraction analysis. The salient features of the present protocol are mild reaction conditions, shorter reaction time, reusability of the catalyst, and applicability to a wide range of substrates. © 2015 Elsevier Ltd.