Used as a key reagent in organic synthesis, particularly in cyclopropanation reactions and as a 1,3-dipole in 1,3-dipolar cycloadditions. It serves as a versatile building block for introducing functionalized ester and ketone groups into molecules. Commonly applied in the preparation of heterocyclic compounds and complex ring systems found in pharmaceuticals and natural products. Its diazo functionality allows for metal-catalyzed insertion reactions, making it valuable in the synthesis of bioactive molecules and fine chemicals.