DACN(Tos,Suc-OH) is a click chemistry reagent featuring a cycloalkyne group. The cycloalkyne unit exhibits a uniquely curved structure and high reactivity towards cycloaddition reactions. Employing cycloalkynes, the strain-promoted azide-alkyne cycloaddition (SPAAC) process has been effectively used for reliable molecular conjugation across various fields. Nitrogen serves as a linkage point for diverse functional units in this context. Additionally, DACN demonstrates considerable click-reactivity, along with enhanced thermal and chemical stability.