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 solvent and condensing agent. The polycyclization occurred at a sufficiently low temperature of 210 degrees C for 2-5 h and resulted in obtaining film-forming PODS having inherent viscosities up to 0.9 dL/g and good thermal stability. 0 2005 Wiley Periodicals, Inc.