A novel, fluorinated diamine monomer, 2,5-bis(4-amino-2-trifluoromethylphenoxy)-tert-butylbenzene (II) was synthesized through the nucleophilic substitution reaction of tert-butylhydroquinone (t-BHQ) and 2-chloro-5-nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound I, followed by catalytic reduction with hydrazine and Pd/C to afford diamine II. A series of fluorinated polyimides V were prepared from II with various aromatic dianhydrides (IIIa-f) via the thermal imidization of poly(amic acid). Most of Va-f could be soluble in amide-type solvents and even in less polar solvents. These polyimide films showed tensile strengths up to 106 MPa, elongation at break up to 21%, and initial modulus up to 2.1 GPa. The glass-transition temperature of V was recorded at 245-304 degreesC, the 10% weight loss temperatures were above 488 degreesC, and left more than 41% residue even at 800 degreesC in nitrogen. Low dielectric constants, low moisture absorptions, and higher and light-colored transmittances were also observed. (C) 2004 Wiley Periodicals, Inc.