Azido-PEG4-nitrile is widely used in bioconjugation and click chemistry applications due to its azide functional group, which allows for efficient and selective reactions with alkyne-containing compounds. This chemical is particularly valuable in the development of bioconjugates, such as antibody-drug conjugates (ADCs), where it serves as a linker to connect therapeutic agents to targeting molecules. Its PEG spacer enhances solubility and reduces steric hindrance, improving the stability and efficacy of the resulting conjugates. Additionally, it is employed in materials science for surface modification and functionalization of nanoparticles, polymers, and biomaterials, enabling the creation of advanced materials with tailored properties. Its versatility also extends to drug delivery systems, where it facilitates the controlled release of active pharmaceutical ingredients.