Two series of related poly(oxadiazole-amide)s have been synthesized by solution polycondensation reaction of aromatic diamines containing preformed 1,3,4-oxadiazole rings with diacid chlorides having silicon or hexafluoroisopropylidene groups. All these polymers were soluble in polar amidic solvents, such as N-methylpyrrolidinone and dimethylformamide and gave thin transparent free-standing films on casting their solutions. The polymers exhibited