The new convenient method for the synthesis of high molecular weight aromatic poly-(1,3,4-oxadiazole)s (PODs) has been proposed. These polymers were prepared by “one–pot” procedure from dicarboxylic acid and hydrazine’s salt (sulfate, phosphate) or dicarboxylic acid dihydrazides. The mixture of ionic liquid and triphenyl phosphite was used both as a a solvent and condensing agent. The polycyclization occurred at sufficiently low temperature equal to 210oC for 2 - 5 hours and resulted in obtaining film-forming PODs having inherent viscosities up to 0.9 dl/g and good thermal stability.