BP Fluor 350 Azide is a blue fluorescent azide-activated probe that can react with terminal alkynes through a copper-catalyzed click reaction (CuAAC). Additionally, it can undergo a copper-free click reaction with strained cyclooctynes, forming a stable triazole without the need for a copper catalyst or high temperatures. This compound is water-soluble, has moderate photostability, and emits blue fluorescence with an optimal excitation wavelength of 350 nm. It is commonly used in imaging and flow cytometry to produce stable signals. The brightness and photostability of the blue dye are ideal for direct imaging of high-abundance targets.