A series of poly(imide-amide)s were synthesized by interfacial condensation of carbomethoxy-iso/terephthaloyl chlorides (I) with aromatic diamines and polycyclic aliphatic diamines. Carbomethoxy-iso/terephthaloyl chlorides, containing approximately 50% para isomer and 50% meta isomer, were synthesized from trimellitic anhydride. The intermediates poly(amide-amic ester)s III had inherent viscosity of 0.1-0.36 dL/g. All poly(amide-amic ester)s were soluble in NMP, DMAc, DMF, and DMSO, except the polymer prepared from 1,6-diaminodiamantane. The poly(amide-amic ester)s were thermally treated to form poly(imide-amide)s. Most of poly(imide-amide)s showed amorphous patterns in x-ray diffraction studies. The glass transition temperatures of these poly(imide-amide)s were in the range of 255-319 degrees C, and the 5% weight loss temperatures in TGA were in the range of 465-540 degrees C in nitrogen. The poly(imide-amide)s (IVe and TVd) from polycyclic aliphatic diamines such as 1,3-diaminoadamantane and 1,6-diaminodiamantane, had good thermal stability, with the temperature at 5% weight loss above 465 degrees C. The poly(imide-amide)s (IVc and IVd) also had high glass transition at 294 degrees and 291 degrees C, respectively.