Diethyl azodicarboxylate is widely used in organic synthesis as a reagent for the Mitsunobu reaction, which is a key method for converting alcohols into esters, ethers, and other derivatives. It facilitates the formation of carbon-nitrogen and carbon-oxygen bonds, making it valuable in the production of pharmaceuticals and fine chemicals. Additionally, it is employed in the synthesis of heterocyclic compounds, which are important in drug development. Its role as a dehydrogenating agent is also notable in the preparation of azo compounds and other organic intermediates.