ATTO 725 azide is an azide derivative of ATTO 725, featuring maximum excitation/emission wavelengths of 728/751 nm. As a click chemistry reagent, it contains an azide group that engages in copper-catalyzed azide-alkyne cycloaddition reactions (CuAAC) with molecules bearing alkyne groups. Additionally, it can undergo strain-promoted azide-alkyne cycloaddition (SPAAC) with molecules containing DBCO or BCN groups.