The direct polymerization of an unsymmetrical kink non-coplanar heterocyclic diamine (1) with various aromatic bis(trimellitimide)s (2a-e) using triphenyl phosphite and pyridine as condensing agents could generate a series of new aromatic poly(amide imide)s (3a-e) containing the kink non-coplanar phthalazinone heterocyclic units in the polymer main chains with inherent viscosities of 0.58-0.66 dL/g. The polymers are readily soluble in a variety of solvents such as N

N-dimethylformamide

N

N-dimethylacetamide

dimethyl sulfoxide

N-methyl-2-pyrrolidinone

pyridine and m-cresol and can be cast to form flexible and tough films. The glass transition temperatures of polymers (Tg) are in the range of 301-327℃

and the temperatures for 5% weight loss in nitrogen are in the range of 498-521 ℃.