Please cite this article as: N.S. Fallah, M. Mokhtary, Tin oxide nanoparticles (SnO 2 -NPs): An efficient catalyst for one-pot synthesis of highly substituted imidazole derivatives, Journal of Taibah University for Science (2015), http://dx. ABSTRACTThe direct three component condensation of 9,10-phenanthraquinone or acenaphthenequinone with aryl aldehyde, and ammonium acetate to generate highly substituted imidazole derivatives has been carried out over tin oxide nanoparticles with high efficiency in ethanol under reflux conditions.