The structure of the 1: 2 adduct of hexamethylenetetramine and thiourea was reanalyzed reinterpreting X-ray diffraction data and providing additional IR and NMR spectroscopic features. The product is thus described as supramolecular commensurate host-guest complex corresponding to the intercalation of hexamethylenetetramine in a layered thiourea matrix. FT-IR spectra evidence a simultaneous strengthening of both C-N and C-S bonds, that appearing as a pattern characteristic for described layered thiourea matrix. 13CP MAS-NMR spectra of the intercalated hexamethylenetetramine is essentially determined by nuclear dipolar magnetic interactions and host-guest chemical interactions arising from 13C-14N residual dipolar interaction not averaged to zero by MAS-NMR and from the magnetic non-equivalence of the guest carbon atoms caused by the hydrogen bonding interaction with the thiourea matrix