AF 430 hydrazide is a derivative of the yellow fluorescent dye AF 430. It has an excitation wavelength of 425 nm and an emission wavelength of 542 nm. AF 430 hydrazide can participate in a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with azide groups and alkynes. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) with molecules containing DBCO or BCN groups, facilitating dye labeling and specific conjugation to biomolecules.