Copper oxide nanoparticles (CuONPs) were successfully decorated on acid treated multi-wall carbon nanotubes ( f -MWCNTs) using copper acetate precursor by a very simple “mix and heat” method, and was used as a heterogeneous nanocatalyst for the N -arylation of imidazole for the first time. The transmission electron microscopic (TEM) images of the prepared nanocatalyst (CuO/MWCNT) showed a good adhesion of CuONPs on anchoring sites of the MWCNTs. The factual loading of Cu in CuO/MWCNT was 7.64 wt% as confirmed by inductively coupled plasma-mass spectrometry (ICP-MS). The chemical state of Cu on MWCNTs was +2 as revealed by wide angle X-ray diffraction (WAXD), X-ray photoelectron spectroscopic (XPS) and temperature programmed reduction (TPR) techniques. Initially the reaction conditions were optimized and then the scope of the catalytic system was extended with different aryl halides . 0.98 mol% (5 mg) of the catalyst was sufficient for N -arylation of imidazole . A literature survey showed that this is the smallest amount of catalyst used for this reaction in research reported to date. The CuO/MWCNT is chemically as well as physically very stable, heterogeneous in nature and reusable. After the catalytic reaction , MWCNTs were successfully separated from the used CuO/MWCNT and characterized by Raman, TEM and WAXD.