Phthalic acid is used as an active ingredient in polyesters and alkyd resins. It is also used as plasticizers for polyvinyl chloride and other polymers. It is also useful in the production of anthraquinone, phenolphthalein and phthalocyanine pigments. It serves as an organic reagent in the production of phthalates. It is used to prepare 1,3-cyclohexadiene by reduction using sodium amalgam.

This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.