Benzothiete () undergoes cycloadditionreactions with hetero dienophiles with NN-, NO- or CO- double bonds, leading to six-membered heterocyclic ring systems of 2H-3,4-dihydro-1,2,3-benzothiadiazine (), 4H-3,1,2-benzoxathiazine () and 4H-3,1-benzoxathiin.