5′-O-DMT-thymidine 3′-CE phosphoramidite is an immensely critical compound employed in the solid-phase synthesis of oligonucleotides, the building blocks of DNA. The chemical is a phosphoramidite derivative of thymidine, which dutifully incorporates into the growing strand of DNA during synthesis, and crucially, in turn, dictates the eventual structure of the resultant chemical entity.