In the title compound, C10H7NO2S2·0.5CH3OH, the dihedral angle between the aromatic rings is 11.43 (11)° and a short intra­molecular C—H⋯S contact occurs. The methanol solvent mol­ecule is equally disordered over two sets of sites. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds occur. The methanol solvent mol­ecule connects the dimers through O—H⋯S and O—H⋯O inter­molecular hydrogen bonds. Further stability is afforded by C—H⋯π and π–π inter­actions [centroid–centroid separation = 3.5948 (13) Å].

The title compound, C12H9BrN2OS·0.06H2O, is a hydrated Schiff base derived from benzoic hydrazide and 4-bromo­thio­phene-2-carboxaldehide. The two Schiff base mol­ecules in the asymmetric unit differ crystallographically: in one mol­ecule the dihedral angle between the benzene ring and thio­phene ring is 49.88 (11)°, whereas the other mol­ecule the rings are almost coplanar with an r.m.s. deviation for the non-H atoms of 0.025 Å. In the crystal, mol­ecules form polymeric sheets linked by N—H⋯O and C—H⋯O hydrogen bonds. The water mol­ecule of crystallization is partially occupied and its H atoms could not be located.

In the title compound, C11H9NO3S2·CH4O, the dihedral angle between the aromatic rings is 3.57 (16)° and intra­molecular O—H⋯O and C—H⋯S inter­actions occur. In the crystal, the thia­zolidin-4-one mol­ecules are linked by N—H⋯O hydrogen bonds, forming chains. The hydrogen-bond motifs lead to S(5), S(6) and R 3 3(8) ring motifs. There exist C=O⋯π inter­actions between the heterocyclic rings and π–π inter­actions between the heterocyclic and benzene rings at distances of 3.455 (2) and 3.602 (2) Å, respectively. The methanol solvent mol­ecule is disordered over two sets of sites in a 0.542 (9):0.458 (9) ratio.

In the title compound, C20H17N3O4, the dihedral angles between the heterocyclic ring and the toluene and nitro­benzene rings are 4.21 (15) and 11.43 (14)°, respectively. The whole mol­ecule is close to planar (r.m.s. deviation for the 27 non-H atoms = 0.171 Å). Two S(6) rings are formed due to intra­molecular C—H⋯O and O—H⋯O hydrogen bonds. In the crystal, inversion dimers linked by pairs of C—H⋯O bonds generate R 2 2(10) loops and further C—H⋯O bonds link the dimers along the b-axis direction. There exist π–π inter­actions between the heterocyclic rings at a centroid–centroid distance of 3.7126 (10) Å and between the centroids of the benzene rings at a distance of 3.8710 (16) Å.

In the title compound, C7H10N+·C2H2ClO2 −, the planar chloracetate ion [with a maximum deviation of 0.025 (3) Å] is oriented at a dihedral angle of 31.07 (4)° with respect to the planar [maximum deviation of 0.022 (3) Å] phenyl­methanaminium cation. In the crystal structure, inter­mol­ecular N—H⋯O hydrogen bonds link the mol­ecules into a network. A weak C—H⋯π inter­action is also present.