Di-tert-butyl terephthalate is primarily used as a plasticizer in the production of polymers and resins. It enhances the flexibility, durability, and processing properties of plastics, making it valuable in manufacturing items like films, coatings, and adhesives. Additionally, it serves as an intermediate in organic synthesis, particularly in the production of specialty chemicals and pharmaceuticals. Its stability and compatibility with various materials make it suitable for applications in the automotive and construction industries, where high-performance materials are required.