During the last century, new families of engineering materials known as polymers have been discovered and produced; those have not challenged the classical materials but have also made possible the realization of new products which have contributed to extend the range of activities of mankind. The Chemistry of macro molecular architectures has gained increased interest in recent years among the polymer chemists. Polyester makes up about 18% of world polymer production and is the third most produced polymer; polyethylene and polypropylene are the first and second, respectively. Epoxy resins are polyether resins containing more than one epoxy group capable of being converted into the thermoset form. In these book we have describe synthesis and characterization of several resins based unsaturated polyesters, prepared by using s-triazine and piperazine derivatives in the chain back bone. This book also includes interacting blends of acrylated polyesters and preparation of composites with their mechanical properties, electrical properties and chemical properties.