A series of new poly(arylene ether 1,3,4-oxadiazole)s has been prepared by nucleophilic displacement of aromatic dihalides with aromatic potassium bisphenates in diphenyl sulfone at elevated temperatures. The polymers, characterized by elemental and infrared analysis, GPC, and wide-angle X-ray diffraction, had inherent viscosity from 0.3 to 0.7 dL/g, were obtained in yields higher than 85%, show good solubility in various organic solvents, and had excellent thermal stability as shown by 10% weight loss temperatures in nitrogen and air (above 445 and 440 degreesC, respectively) and high glass transition temperatures (in the range of 188-226 degreesC). The introduction of two 1,3,4-oxadiazole units in the polymer repeat unit determines glass transition temperatures higher than those of similar polymers containing only one oxadiazole group in the repeat unit.