Used as a key intermediate in the synthesis of pharmaceutical compounds, particularly in the development of kinase inhibitors and antimicrobial agents. Its sulfonyl chloride group readily reacts with nucleophiles, enabling efficient coupling with amines or alcohols to form sulfonamides or sulfonate esters, which are common pharmacophores. It is also employed in the preparation of fluorescent probes and dyes due to the quinoxaline core’s favorable photophysical properties. Commonly utilized in medicinal chemistry for structure-activity relationship (SAR) studies to optimize drug candidates.