Benzo[2,3]naphtho[5,6,7-ij[l,4]dithiepin was prepared by the condensation of the disodium salt of 1,2-dimercaptobenzene with 1-chloro-8-nitronaphthalene. The structure was established by nmr and mass spectroscopy. A small quantity of benzo[2,3]naphtho[5,6,7-ij][1-4]dithiepin 1-oxide was also isolated. The structure was initially established by mass spectrometry. The proton spectrum was totally assigned using a combination of proton zero quantum coherence (ZQCOSY) and proton-carbon heteronuclear chemical shift correlation (HC-COSY) techniques, which also allowed the unequivocal assignment of the protonated carbon resonances. An X-ray crystal structure of the 1-oxide irrefutably confirmed the structure. The crystal was triclinic and the space group was PI, and the data refined to a final R = 0.0353. The molecule was shown to be folded about the axis passing through the two sulfur atoms with a dihedral angle of 109.00°.