N3-Gly-Gly-Gly-OH is a low-molecular-weight oligo-glycine chemical reagent featuring an azide group. This compound is also utilized as a linker for connecting subunits of dimeric or oligomeric proteins and synthesizing artificial multidomain proteins. By modifying it to the Gly-Gly-Gly-Ser sequence, enhanced solubility is obtained. Additionally, N3-Gly-Gly-Gly-OH serves as a click chemistry reagent capable of undergoing copper-catalyzed azide-alkyne cycloaddition reactions (CuAAC) with molecules that contain an alkyne group. It can also participate in strain-promoted azide-alkyne cycloaddition reactions (SPAAC) with molecules containing DBCO or BCN groups.