Crystal structures and Hirshfeld surface analyses of (E)-N′-benzyl­idene-2-oxo-2H-chromene-3-carbo­hydrazide and the disordered hemi-DMSO solvate of (E)-2-oxo-N′-(3,4,5-trimeth­oxybenzyl­idene)-2H-chromene-3-carbohydrazide: lattice energy and inter­molecular inter­action energy calculations for the former

The crystal structures of the disordered hemi-DMSO solvate of (E)-2-oxo-N′-(3,4,5-tri­meth­oxy­benzyl­idene)-2H-chromene-3-carbohydrazide, C(20)H(18)N(2)O(6)·0.5C(2)H(6)OS, and (E)-N′-benzyl­idene-2-oxo-2H-chromene-3-carbohydrazide, C(17)H(12)N(2)O(3) (4: R = C(6)H(5)), are discussed. The non-hydrogen atoms in compound [4: R = (3,4,5-MeO)(3)C(6)H(2))] exhibit a distinct curvature, while those in compound, (4: R = C(6)H(5)), are essential coplanar. In (4: R = C(6)H(5)), C—H⋯O and π–π intra­molecular inter­actions combine to form a three-dimensional array. A three-dimensional array is also found for the hemi-DMSO solvate of [4: R = (3,4,5-MeO)(3)C(6)H(2)], in which the mol­ecules of coumarin are linked by C—H⋯O and C—H⋯π inter­actions, and form tubes into which the DMSO mol­ecules are cocooned. Hirshfeld surface analyses of both compounds are reported, as are the lattice energy and inter­molecular inter­action energy calculations of compound (4: R = C(6)H(5)).