Alternate poly(amide-imide) [P(A-alt-I)] was synthesized from two aromatic diamines and trimellitic anhydride (TMA). When the diamine was 2,2-bis[4-(3-amino phenoxy)phenyl] sulfone (BAPS), the resulted P(A-alt-I) was found to be of light color. Specifically, when BAPS was located between two amide groups in the P(A-alt-I) chain, the P(A-alt-I) was almost colorless. A series of P(A-alt-I)s (Series III) containing BAPS was synthesized through direct polycondensation of an aromatic dicarboxylic acid prepared from various aromatic diamines and TMA, as well as BAPS. Polymers of Series III were much lighter in color than those of the isomeric series (BAPS was located between two imide group). The series of P(A-alt-I)s III had inherent viscosities ranging 0.69-1.35 dL/g and good solubility in various solvents. The tensile strengths, elongations to break, and initial moduli of the films were 72-107 MPa, 7-12% and 1.93-2.39 GPa, respectively, and most of the films had no yielding. Polymers of Series III had glass transition temperatures 210-272 degrees C and 10% weight loss temperatures in nitrogen 518-545 degrees C, indicating excellent thermal stability.