Used as an intermediate in the synthesis of dyes and pigments due to its reactive sulfonyl chloride group, which readily undergoes substitution reactions. Employed in the preparation of sulfonamide derivatives with potential biological activity, making it valuable in medicinal chemistry research. Its naphthalene core allows for extended conjugation, useful in developing fluorescent probes or organic semiconductors. Also applied in polymer chemistry to introduce naphthoate ester functionalities for modifying resin properties.