Pyromellitic dianhydride (1) was reacted with L-leucine (2) to result [N, N'-(pyromellitoyl)-bis-L-leucine diacid] (3). This compound (3) was converted to N,N'-(pyromellitoyl)-bis-L-leucine diacid chloride (4) by reaction with thionyl chloride. Polycondensation reaction of this diacid chloride (4) with polyethyleneglycol-diol (PEG-200) and/or three synthetic aromatic diols furnish a series of new PEIs and Co-PEIs. Polycondensation was carried out in the presence of triethylamine (TEA) or pyridine (Py) as a catalyst in different solvents, at different reaction times and temperatures. The resulting polymers and copolymers have inherent viscosities in the range of 0.10-0.33 dl g(-1). These polymers are optically active, thermally stable and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc and sulfuric acid. All of the above polymers were fully characterized by IR spectroscopy, H-1 NMR spectroscopy, elemental analyses, specific rotation and thermal analyses. Some structural characterizations and physical properties of these optically active PEIs and Co-PEIs are reported. (c) 2007 Elsevier Ltd. All rights reserved.