The synthesis of 4-aryl-NH-1,2,3-triazoles in good to excellent isolated yields (75-95%) has been achieved via a [3+2] cycloaddition of aromatic nitroolefins and sodium azide catalyzed by recyclable heterogeneous sulfated tin oxide (STO, 10 mol%) in toluene at 60 0C. Aliphatic nitrooefines proved to be unsuccessful partners in the present methodology.