A new dicarboxylic acid containing a diphenylmethylene linkage, bis[4-(4-carboxyphenoxy)phenyl] diphenylmethane (BCAPD), was prepared from bis(4-hydroxphenyl)diphenylmethane and p-fluorobenzonitrile via an aromatic nucleophilic substitution reaction followed by hydrolysis. A series of novel polyamides were prepared by the direct polycondensation of BCAPD and various aromatic diamines. The polymers were produced with moderate to high inherent viscosities of 0.80-0.85 dL g(-1). Nearly all the polymers were readily soluble in polar solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide, in less polar solvents such as pyridine and cyclohexanone, and in tetrahydrofuran. All the polymers were amorphous, and the polyamide films had a tensile strength and a tensile modulus greater than 80 MPa and 2.0 GPa, respectively. These polyamides had glass-transition temperatures between 249 and 274 degreesC, and their temperatures at a 10% weight loss were 477-538 and 483-540 degreesC in nitrogen and air atmospheres, respectively. (C) 2001 John Wiley & Sons, Inc.