Syndiotactic potystyrene (SPS) is a new semi-crystalline polymer under development by Dow Plastics, a business group of The Dow Chemical Company. The material is differentiated from conventional styrenic polymers in terms of microstructure and physical properties and represents the basis for an entirely new family of materials derived from crystalline polystyrene. SPS exhibits excellent thermal performance with a melting point of 270° C (520° F) combined with resistance to moisture and automotive fluids. Products produced from SPS demonstrate exceptional electrical performance, low specific gravity, competitive toughness and high modulus relative to other semi-crystalline engineering polymers. A wide range of products have been formulated including impact modified and glass reinforced resins for use in specific markets. This paper discusses the performance attributes of SPS in high performance applications where a combination of heat resistance, chemical resistance and dimensional stability are required.