The 1H and 13C NMR spectra of some novel 1,2,4‐triazolo [1,3] thiazinoquinoline isomeric pairs are interpreted in terms of structural assignments. The structure of most compounds has been confirmed by NOE difference spectroscopy. Characteristic differences have been observed in both 1H and 13C NMR spectra of these isomeric Pairs: some of the 1H and 13C chemical shifts, and also the one bond 13C1H couplings of triazole protons, differ consistently in the NMR spectra of the isomers. The coupling constants have been determined using a combination of INEPT and chemical shift selective filtering.