chloroformamidines 1 reacted with 2-aminophenols 2 to give 4-dialkylamino [1,2,3,5] benzoxathiadiazepine dioxides 3, which are examples of a new ring system. Reaction of 1 with 1,2-diaminobenzenes 7 afforded 4-dialkylamino[2,1,3,5]benzothiatriazepine dioxides 8 and 9, which are new derivatives of a rare ring system. Some N-alkyl and N-acyl derivatives of 3 and 8 were prepared to demonstrate the potential of these compounds as novel scaffolds for synthetic and medicinal chemistry.