New fluorinated aromatic polyimides were prepared from 1,4-(4 ' -aminophenoxy)-2-(3 ' -trifluoromethylphenyl)benz and aromatic dianhydrides via the polycondensation of one-step high-temperature and two-step thermal or chemical imidization methods. Experimental results indicated that some of the polyimides were soluble both in strong dipolar solvents (N-methyl-2-pyrrolidone or N,N-dimethylacetamide) and in common organic solvents such as tetrahydrofuran, CHCl3, and acetone. The polyimides showed exceptional thermal and thermooxidative stability and good mechanical properties. No weight loss was detected before a temperature of 520 degreesC in nitrogen, and the glass-transition temperatures ranged from 208 to 251 degreesC. Low dielectric constants (2.55-2.71 at 1 MHz), low refractive indices, and low water absorption were also observed.