A facile and convenient metal-free direct oxidative amination of acetonitrile followed by cyclization with aroyl hydrazide for synthesizing oxadiazoles has been investigated. Disubstituted 1,3,4-oxadiazoles were obtained at 50-82% yields using readily available acetonitrile as both reagent and solvent. In addition, the reaction of aroyl hydrazides with thioacetamide and cyanothioacetamide afforded 5-methyl-2-aryl-1,3,4-thiadiazoles and 2-aryl-1,3,4-oxadiazole-2-acetonitriles as the main products, respectively.