Environmentally Friendly Multicomponent Polyfunctional Vinyl Esters Were Developed. They Were Nontoxic, Nonvolatile And Solvent Free Thermally Stable Liquids With Intended And Controllable Processing Viscosities. The First Vinyl Ester, Bisphenol- A-Glycidyldimethacrylate (Bisgma) Prepolymer Was Synthesized From Methacrylic Acid And Diglycidyl Ether Of Bisphenol-A-Type Epoxy Resin Using Triphenylphosphine As A Catalyst. To Study The Effect Of Reactive Diluent On Vinyl Ester Resin, A New Reactive Diluent Was Synthesized In Our Laboratory Which Was Based On Nonyl Phenol. This Reactive Diluent Was Not Volatile Organic Compounds (Voc) And Was Not Creating Hazardous Air Pollutants (Hap). This Reactive Diluent Had Very Low Viscosity And Easily Forms Compatible Mixture With Bisgma Resin. Finally Its Toughening Characteristic With Bisgma Resin Was Studied. To Study The Effect Of Reinforcing Filler With Vinyl Ester Resin, Two Nanocomposites Were Fabricated. One With Acid Treated Multi-Walled Carbon Nanotubes And Another With Nano Titania. In Bisgma-Tio2-Nanocomposite, The Flexural Modulus, Storage Modulus, Tg And Thermal Stability Increased With Increasing Percentage Of Loading. Increasing Of Particle Loading Reached An Optimum Value At 1% Tio2 And Than Decreased.Similarly In Bisgma/Mwcnt Composites, Composite Containing 1wt% Acid Treated Mwcnt Exhibited Relatively Good Elastic Modulus, Yield Strength, Increase In The Glass Transition Temperature And Decrease In The Failure Strain To That Of Pure Resin. Again For A Low Cost Housing Project And To Study The Effect Of Fibrous Filler On Vinyl Ester Resin, A 5 Layer Jute Fiber Composite Was Prepared. Here Jute Fiber Was Treated With A Coupling Agent 2-Hydroxyethyl Acrylate (Hea). This Composite Offer The Unique Potential Of Combining Natural Fibers With Resins Based On Natural Renewable Resources [Soybean Oil]. Bending Strength (Bs), Bending E-Modulus And Storage Modulus Of The Hea Treated Jute–Esoa Composite Was Increased As Compared To The Untreated One At 400c Respectively. The Sem Of The Tensile Fracture Surfaces Showed Improved Interfacial Adhesion Between Treated Jute With Esoa. Finally To Study The Effect Of Thermoplastics On Vinyl Ester Resin, Different Blends Were Studied. From The Experimental Results It Was Found That, Pvp/Bisgma