· 4-Chloro-3-nitrobenzenesulfonyl chloride is used in the preparation of functionalized 1H-indenes via copper-catalyzed arylative cyclization. · It is a precursor in the synthesis of N-arylsulfonyl-3-acylindole arylcarbonyl hydrazone derivatives that show potential nematicidal activity. · It is a key starting material in the synthesis of sulfonamide analogs of ferrostatin-1 (fer-1), which possess good ferroptosis inhibition property. · It can also be used in the synthesis of 4-chloro-3-nitrobenzene thiol.