SDA azide contains both diazirine photoaffinity moiety and azide functional group. It is an excellent building block to introduce photoaffinity function into an alkyne-modified biomolecule via the well-known click chemistry. Diazirines are known for their ability to undergo photochemical reactions when exposed to ultraviolet (UV) light, specifically by forming highly reactive carbene intermediates that react with nearby molecules, forming covalent bonds. This property makes diazirines useful for studying protein-protein, protein-nucleic acid interactions, ligand-receptor binding, and other biomolecular interactions. It's important to note that diazirines are highly reactive and can be challenging to handle due to their instability. They require careful storage and handling, typically in a controlled environment. Additionally, the choice of diazirine-containing compound and the conditions of the photolabeling experiment must be carefully optimized to achieve desired results while minimizing non-specific reactions.