A fluorinated aromatic polyanhydride (B) was synthesized from the melt condensation of mixed anhydrides of 4,4'-(hexafluoroisopropylidene)bis benzoic acid. Although the mixed anhydride from acetic anhydride yielded only a mixture of oligomers (weight-average molecular weight < 2000), higher weight-average molecular weight materials in the range of 15,000-18,000 were obtained with trifluoroacetic anhydride. Polymer B was soluble in chloroform and tetrahydrofuran, had a relatively high glass-transition temperature of 176 degreesC with no melting point detected to 310 degreesC, and showed excellent thermal stability (5% weight loss observed at 380 degreesC by thermogravimetric analysis). The hydrolytic degradation of the fluorinated polyanhydride in a 0.1 M phosphate buffer of pH 7.4 at 37 degreesC was initially zero-order, with 35% degradation occurring in 10 days. Loss of film integrity following that led to accelerated degradation, and almost complete dissolution was observed by the 16th day. The stability of the fluorinated polyanhydride in the solid state and in the solvent tetrahydrofuran was also evaluated.