4-azidobutyric acid is primarily used in chemical synthesis and bioconjugation processes. It serves as a versatile building block in the preparation of various organic compounds, particularly in click chemistry reactions. The azide group in its structure allows for efficient and selective coupling with alkynes, making it valuable for labeling biomolecules, such as proteins and nucleic acids, in research and diagnostic applications. Additionally, it is employed in the development of polymer materials and drug delivery systems, where its reactive azide group facilitates the incorporation of functional groups or targeting moieties. Its role in bioorthogonal chemistry also supports advancements in live-cell imaging and the study of biological processes.