N6-[[(4-Azidophenyl)methoxy]carbonyl]-L-lysine is an unnatural amino acid. N6-[[(4-Azidophenyl)methoxy]carbonyl]-L-lysine is a click chemistry reagent, it contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups.