The title compound, 4,7-dioxa-10-thia-1,12,13-triazabicyclo[9.3.0]tetradeca-11,13-diene, C(8)H(13)N(3)O(2)S, contains an 11-membered ring, which appears in a chair conformation and has approximate mirror symmetry. It may be used for the complexation of metal atoms.