A novel diamine 2H-(4-aminophenyl)-4-(3-phenyl-4-aminophenoxy)-2

3-phthalazin-1-one (1) containing N—C coupling bond was synthesized and reacted with four aryl diimide-dicarboxylic acids to prepare a series of new aromatic poly(amide imide)s via direct polycondensation using Yamazaki phosphorylation procedure．The polymers obtained in high yield had high molecular weight with the inherent viscosity in the range of 0.50～0.70 dLg-1．Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that the polymers had high glass transition temperature of 317～343℃ and good thermostability with 10％ weight loss temperature above 440℃．They were readily soluble in polar solvents such as NMP、DMF and m-cresol etc and clear

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flexible films can be cast from their DMAc solutions．The structure of monomer and their polymers was characterized by MS、FT-IR and 1H-NMR and they are consistant with the proposed structure．X-ray diffraction showed that all poly(amide imide)s were amorphous．