Vinyl ester (VE) resins that are employed in many commercial applications need diluents to allow the resins to be molded using liquid molding techniques. These diluents are typically volatile organic compounds that should be avoided to reduce health and environmental risks. Therefore, chemically modified fatty acid methyl ester (CMFAME) from soybean and linseed oil were synthesized and employed as a diluent for VE resins. The effect of the weight ratio of CMFAME to VE on the resin and polymer were analyzed by studying the rheometric and mechanical properties, respectively. The viscosity of these resins and the mechanical properties of the bio-based polymers were analyzed. The viscosity of VE/CMFAME resins and glass transition decreased as the content of CMFAME increased. These resins have properties that are comparable to commercial resins. Also, a chemical modified lignin (butyrated kraft lignin) was added to these resins (VE/CMFAME) and the mechanical properties of the polymer were improved.