7-(2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)heptanoic acid is a heterobifunctional linker featuring a maleimide group and a carboxylic acid terminus. It is primarily used in bioconjugation chemistry, where the maleimide selectively reacts with thiol groups (e.g., cysteine residues) via Michael addition, enabling the attachment of biomolecules, drugs, or labels to proteins, antibodies, and nanoparticles. The carboxylic acid can be activated (e.g., with EDC/NHS) for coupling to amine groups, facilitating applications in targeted drug delivery, immunotherapy, and diagnostic assays. In polymer science, it serves as a crosslinker for thiol-containing polymers, enhancing network formation in hydrogels, biocompatible coatings, and surface modifications for biomedical devices.