Used primarily as an intermediate in the synthesis of functionalized polymers and bioconjugates. Its reactive acid chloride group enables coupling with amines or alcohols to form amide or ester linkages, making it valuable in modifying surfaces or attaching functional moieties in pharmaceutical and material science applications. The phthalimide-like structure provides stability and can act as a protecting group or a chromophore in detection systems. Commonly employed in the development of photoactive compounds, sensors, and drug delivery platforms where controlled reactivity and structural rigidity are required.