H2N-PEG4-Hydrazide is widely used in bioconjugation and chemical modifications due to its hydrazide and amine functional groups. It serves as a linker in the synthesis of protein-drug conjugates, enabling the attachment of therapeutic agents to proteins or antibodies for targeted drug delivery. The compound is also employed in the preparation of PEGylated biopolymers, enhancing their solubility and stability. Additionally, it is utilized in the development of biosensors and diagnostic probes, where its reactive groups facilitate the attachment of biomolecules to surfaces or other functional entities. Its PEG spacer provides flexibility and reduces steric hindrance, making it a valuable tool in biotechnological and pharmaceutical research.