Bis-Mal-Lysine-PEG4-TFP ester is widely used in bioconjugation and protein modification applications. Its bifunctional structure allows it to act as a crosslinker, enabling the attachment of two molecules through specific reactive groups. The maleimide groups in the compound specifically target thiols, making it ideal for coupling with cysteine residues in proteins or peptides. The TFP ester group reacts efficiently with amines, facilitating conjugation with amino-containing molecules. This compound is particularly valuable in antibody-drug conjugate (ADC) development, where it helps link cytotoxic drugs to antibodies for targeted cancer therapy. Additionally, it is employed in the synthesis of peptide-based therapeutics, diagnostic probes, and biomaterials, where precise and stable conjugation is essential. The PEG4 spacer enhances solubility and reduces steric hindrance, improving the efficiency of the conjugation process.