Two fluorinated aromatic bis(o-aminophenol)s, 1,1bis(3 0 -amino-4 0 -hydroxyphenyl)-1-(3 0 -trifluoromethylphenyl)-2,2, 2-trifluoroethane (6FAP) and 1,1-bis(3 0 -amino-4 0 -hydroxyphenyl)-1-(3 0 ,5 0 -ditrifluoromethylphenyl)-2,2,2-trifluoroethane (9FAP) were synthesized, which were allowed to polycondense with aromatic diacyl chlorides to afford the fluorinated aromatic polybenzoxazoles (PBOs) via a conventional two-step procedure in which the low-temperature solution polycondensation process was first performed to yield poly(o-hydroxyamide)s (PHAs) followed by the thermal cyclodehydration to give the PBOs. Experimental results indicated that the PHAs had inherent viscosities in the range of 0.29-0.68 dL/g, showing excellent solubility in organic solvents. The PHAs could be thermally cyclodehydrated into the corresponding PBOs at 260-370 C. The obtained PBOs exhibited enhanced glass-transition temperature but decreased solubility with respect to the PHAs. The PBOs showed glasstransition temperatures in the range of 315-337 C and excellent thermal stabilities with 5% original weight-loss temperatures (T 5 ) of >513 C. Additionally, the PBO films had average refractive index of 1.5298-1.5656, birefringence of 0.0051-0.0092, and low dielectric constants of 2.57-2.70. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4668][4669][4670][4671][4672][4673][4674][4675][4676][4677][4678][4679][4680] 2010 Materials 3 0 -Trifluoromethyl-2,2,2-trifluoroacetophenone (6FK) and 3 0 ,5 0ditrifluoromethyl-2,2,2-trifluoroacetophenone (9FK) were synthesized in our laboratory according to the previously reported