Thiophene and their derivatives products are some of the oldest and best known class of nitrogen and sulphur containing compounds. In recent years there has been considerable interest in the thiophene -based family of materials due to the wide range of antimicrobial activity properties when incorporated into polymers and their composites. In this research new modified polyesteramide resin compositions which are prepared by partial replacement of phthalic anhydride (PA) with 3,6-dichloro bezo[b]- thiophene-2carbonyl glutamic acid (DCBTGA), as a new source of the dibasic acid and as preservative against microbiological attack with N, N- bis - (2-hydroxyethyl) linseed oil fatty acid amide (HELA)  as source of polyol. These new source of  dicarboxylic acid  materials and new modified polyesteramide resin are confirmed by IR and NMR spectral analysis. The coating performance of the resins is evaluated using international standard test methods (ASTM) and involved the measurement of phyisco- mechanical properties such as viscosity, drying time, specular gloss, pencil hardness, adhesion, flexibility and  The results show that the modification enhances both phyisco- mechanical and chemical properties The new antimicrobial polyesteramide resins is characterized using standard (Kathon LX biocide) in different excess – OH formulations  to reach the best formula against bacteria and fungi. The studies showed promising results as biocide coatings.