The asymmetric unit of the title compound, C17H12O4, consists of two independent mol­ecules. The chromen-2-one ring and the 4-methyl­benzoate side chain are inclined to one another at a dihedral angle of 64.79 (10)° in one mol­ecule and 88.3 (1)° in the other. In the crystal, mol­ecules form R 2 2(8) centrosymmetric dimers via C—H⋯O hydrogen bonds. These dimers are stacked by C—H⋯O hydrogen bonds, resulting in R 2 2(18) and R 3 2(16) ring motifs. π–π stacking inter­actions between two parallel chromen-2-one rings, with centroid–centroid distances of 3.743 (1) and 3.771 (1) Å, are also present.

The title compound (C12H10O4) crystallizes in the triclinic space group P1̄ with a = 7.367(3), b = 8.1188(3), c = 9.549(5) Å, α = 74.034(1)°, β = 84.374(2)°, γ = 64.581(3)°, Z = 2, and dcalc = 1.462 g cm−3. It exhibits a strong intramolecular O-H···O hydrogen bond and exists as the exocyclic enolic tautomer as it has been observed in solution. The structure is stabilized by C-H···π, C-O···π and π-π stacking interactions between benzene and pyran rings.

In the title mol­ecule, C17H12O5, the chromen-2-one ring and the 4-meth­oxy­benzoate side chain are inclined to one another at a dihedral angle of 69.82 (9)°. The crystal structure features parallel sheets of centrosymmetric R 2 2(6) dimers joined by a C(7) chain, resulting in centrosymetric tetra­mers of hydrogen-bonded mol­ecules with graph-set motif R 4 4(40). These centrosymetric tetra­mers are connected by a pair of hydrogen bonds described by an R 2 2(8) ring motif and a C(7) chain via C—H⋯O inter­actions. In the structure, there are also π–π stacking inter­actions between chromene benzene and the six-membered heterocyclic rings [centroid–centroid distance = 3.691 (2) Å] and weak C=O⋯π inter­actions [O⋯(ring centroid) distance = 3.357 (3) Å].

In the molecule of the title compound, C14H12N2S, the benzimidazole ring system and the phenyl ring form a dihedral angle of 81.36 (7)°. The crystal structure exhibits intermolecular C—H...N and N—H...N hydrogen bonds.