2-amino-5-aryloxymethyl-1, 3, 4-thiadiazoles were synthesized rapidly by a microwave- accelerated solvent-free procedure in high yield via the condensation of thiosemicarbazide with aryloxyacetic acids using poly (ethylene glycol) supported dichlorophosphate as a dehydration reagent. The solvent-free N-acylation of 2-amino-5-aryloxymethyl-1, 3, 4- thiadiazoles with coumarin-3-carboxylic acid chloride or benzofuran-2-carboxylic acid ...