4-Azidotoluene solution is primarily used in organic synthesis and material science due to its reactive azide group. It serves as a key intermediate in click chemistry reactions, particularly in the formation of triazole compounds through azide-alkyne cycloaddition. This reaction is widely employed in drug discovery, bioconjugation, and polymer chemistry to create complex molecules with high specificity and efficiency. Additionally, it is utilized in photoaffinity labeling studies to investigate protein-ligand interactions and identify binding sites. Its application also extends to the development of advanced materials, such as functionalized surfaces and cross-linked polymers, where its reactivity enables precise modifications.