Used in organic synthesis as an intermediate for pharmaceuticals and fine chemicals. It serves as a building block in the development of bioactive molecules, particularly in the preparation of compounds with potential antimicrobial and anti-inflammatory properties. Also employed in research settings for the synthesis of fluorescent dyes and optical brighteners due to its phthalide core, which can exhibit luminescent characteristics. Its structure allows for easy modification, making it valuable in the design of new chemical entities in medicinal chemistry.