A series of molecular-weight-controlled fluorinated aromatic polyimides were synthesized through the polycondensation of a fluorinated aromatic diamine, 1,4-bis(4'-amino-2'-trifluoromethylphenoxy)benzene, with 4,4'-oxydiphthalic anhydride in the presence of phthalic anhydride as the molecular-weight-controlling and endcapping agent. Experimental results demonstrated that the resulting polyimides could melt at temperatures of 250-300 degrees C to give high flowing molten fluids, which were suitable for melt molding to give strong and flexible polyimide sheets. Moreover, the aromatic polyimides also showed good solubility both in polar aprotic solvents and in common solvents. Polyimide solutions with solid concentrations higher than 25 wt % could be prepared with relatively low viscosity and were stable in storage at the ambient temperature. High-quality polyimide films could be prepared via the casting of the polyimide solutions onto glass plates, followed by baking at a relatively low temperature. The molten behaviors and organosolubility of the molecular-weight-controlled aromatic polyimides depended significantly on the polymer molecular weights. Both the melt-molded polyimide sheets and the solution-cast polymer films exhibited outstanding combined mechanical and thermal properties. (c) 2006 Wiley Periodicals, Inc.