In this project, novel optically active polyamides (PA)s, poly(amide-imide)s (PAI)s and segmented poly(amide-imide-ether-urethane)s (PAIEU)s based on L-leucine, L-isoleucine, L-methionine, L-phenylalanine and S-valine were synthesized. Some physical properties of them were investigated. Starting from L-isoleucine, phthalic anhydride and 5-aminoisophthalic acid moities, new optically active diacid, 5-(3-methyl-2-phthalimidylpentanoylamino)isophthalic acid (MPPAIP) was synthesized in three steps and the structure of this new monomer was confirmed by elemental analysis, FT-IR, 1 H-NMR and 13 C-NMR spectroscopy. Then polyamides were synthesized by direct polycondensation of MPPAIP with aromatic diamines in the presence of the condensing agent such as TPP/Py/CaCl 2 /NMP. Inherent viscosity of these polymers were in the range of 0.21-0.45 dL/g and it showed good solubility and thermal stability. It seems the existence of the imide pendent group in the polymer residue causes this good thermal stability. In second part of this work a series of new poly(amide-imide)s were prepared by direct polycondensation of N -trimellitylimido-L-isoleucine with diisocyanates. The type of catalyst and solvent was optimized for the reaction of this monomer with MDI as a diisocyanate. The optimized conditions was used in the other polycondensations. These polymers have inherent viscosities in the range of 0.13-0.48 dL/g and moderate yields and thermal stability. At the end of this investigation, a series of (PAIEU)s were prepared by copolymerization of diacids containing different amino acid and trimellitic anhydride as monomers with MDI as a diisocyanate. These polymers also showed inherent viscosity in the range of 0.25-0.76 dL/g and good thermal stability. All of the above polymers were fully characterized by FT-IR, 1 H-NMR spectroscopy and elemental analysis. Also thin traarent films of these polymers can be prepared.