The title hydrazine carbodithioate, C13H18N2OS2, is constructed about a central and almost planar C2N2S2 chromophore (r.m.s. deviation = 0.0263 Å); the terminal methoxybenzene group is close to coplanar with this plane [dihedral angle = 3.92 (11)°]. The n-butyl group has an extended all-trans conformation [torsion angles S—Cm—Cm—Cm = −173.2 (3)° and Cm—Cm—Cm—Cme = 180.0 (4)°; m = methylene and me = methyl]. The most prominent feature of the molecular packing is the formation of centrosymmetric eight-membered {...HNCS}2 synthons, as a result of thioamide-N—H...S(thioamide) hydrogen bonds; these are linked via methoxy-C–H...π(methoxybenzene) interactions to form a linear supramolecular chain propagating along the a-axis direction. An analysis of the calculated Hirshfeld surfaces and two-dimensional fingerprint plots point to the significance of H...H (58.4%), S...H/H...S (17.1%), C...H/H...C (8.2%) and O...H/H...O (4.9%) contacts in the packing. The energies of the most significant interactions, i.e. the N—H...S and C—H...π interactions have their most significant contributions from electrostatic and dispersive components, respectively. The energies of two other identified close contacts at close to van der Waals distances, i.e. a thione–sulfur and methoxybenzene–hydrogen contact (occurring within the chains along the a axis) and between methylene-H atoms (occurring between chains to consolidate the three-dimensional architecture), are largely dispersive in nature.

The asymmetric unit of the title compound, C17H17NO2, contains two crystallographically independent mol­ecules. Both mol­ecules adopt a trans configuration about the C=C bond, with the C—C=C—C fragments in the two mol­ecules twisted in opposite directions [torsion angles of 174.2 (2) and −175.8 (2)°]. The two benzene rings in each of the mol­ecules make dihedral angles of 20.21 (6) and 48.64 (4)°. In the crystal, adjacent mol­ecules are linked by O—H⋯O hydrogen bonds into infinite polymeric chains.