A novel fluorinated diamine monomer based on 4,4'-biphenol was synthesized via a straightforward, high-yielding two-step procedure. 4,4'-Biphenol was reacted with 2-chloro-5-nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound, which was subsequently reduced to afford the fluorinated diamine, 4,4'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl. A series of organosoluble fluorinated polyimides were prepared from the diamine with various aromatic dianhydrides via a conventional two-step thermal imidization method. All polyimides were soluble in strong dipolar solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide. The polyimides showed excellent thermal and thermooxidative stability and good mechanical properties. No significant weight loss was observed below a temperature of 520 degreesC in nitrogen or in air, and the glass-transition temperatures ranged from 247 to 313 degreesC. Low dielectric constants (2.57-3.65 at 10 kHz), low moisture absorption (0.1-0.7 wt %), and low color intensity were also observed.