Two novel diamine monomers, 1,4-bis (4-aminophenoxy)-2-[(3',5'-ditrifluoromethyl)phenyl]benzene and 1,4-bis [2'-cyano-3'(4"-amino phenoxy)phenoxy]-2-[(3',5'-ditrifluoromethyl)phenyl] benzene, were synthesized from (3,5-ditrifluoromethyl)phenylhydroquinone. A series of ditrifluoromethylated aromatic polyimides derived from the diamines were prepared through a typical two-step polymerization method. These polyimides had a high thermal stability, and the temperatures at 10% weight loss were above 507 degrees C in nitrogen. Most of the polymers showed good solubility in anhydrated 1-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, chloroform, and tetrahydrofuran at room temperature. All the polymers formed transparent, strong, and flexible films with tensile strengths of 63.6-95.8 MPa, elongations at break of 5-10%, and Young's moduli of 2.38-2.96 GPa. The dielectric constants estimated from the average refractive indices are 2.69-2.89. (c) 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3018-3029, 2005.