A biologically active diacid monomer, 5-(2-phthalimidoethanesulfonamido) isophthalic acid (6), based on taurine, was easily prepared in three steps. Also a series of novel biologically active polyesters (PE)s were synthesized by the reaction of this monomer with several aromatic diols by step growth polymerization using tosyl chloride (TsCl)/dimethylformamide (DMF)/pyridine (Py) system as a condensing agent. The resulting new polymers were obtained in good to high yields with moderate inherent viscosities. All of the PEs were characterized by FTIR and some of them were also characterized by H-1-NMR and elemental analyses methods. The thermal stability of PEs was evaluated with thermogravimetric analysis and differential scanning calorimetry techniques under a nitrogen atmosphere and it was found that they have moderate stability. Wheat seedlings were normally grown in the presence of 6 and it's derived PEs in soil. Also the high dehydrogenase activities in treated soils with obtained compounds showed biodegradability of polymers under soil burial in natural environments. It can be concluded that the synthesized compounds derived from taurine are possibly biologically active and environmentally nontoxic for soil microorganisms. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2573-2583, 2011