The 1H and 13C NMR spectra of three isomeric dinaphthothiophenes are recorded. Chemical shift assignments were made on the basis of substituent chemical shift (SCS) effect arguments, coupling considerations, proton-proton auto-correlated homonulcear (COSY) two-dimensional spectroscopy, and proton-carbon heteronuclear correlation (HETCOR) two-dimensional spectroscopy. Some previously published 1H chemical shifts and coupling constants are compared with our data and some divergences are noted. © 1990.