In the title compound, C21H14BrNO3S, the indole ring system forms dihedral angles of 65.64 (8) and 59.30 (8)°, respectively, with the phenyl and bromo­phenyl rings. In the crystal, mol­ecules are connected by a C—H⋯O hydrogen bond, forming a chain along [101]. The chains are further connected by weak inter­molecular C—H⋯π inter­actions, forming a layer parallel to the ac plane.

In the title compound, C18H11NO, the carbazole and benzofuran rings are almost co-planar, making a dihedral angle of 3.31 (3)°. The crystal structure is stabilized by weak C—H⋯π inter­actions.

In the title compound, C14H14N2O3, the dihedral angle between the pyrimidine and benzene rings is 14.9 (1)°. The mol­ecular structure is stabilized by weak intra­molecular C—H⋯O inter­actions and the crystal structure exhibits a weak inter­molecular π–π inter­action [centroid–centroid distance = 3.575 (3) Å].

In the title compound, C24H15NO3S, the dihedral angle between the phenyl ring and the carbozole system is 74.91 (6)°. The S atom exhibits a distorted tetra­hedral geometry [N—S—C = 104.85 (8)°; O—S—O = 119.59 (9)°]. The crystal structure is established by weak inter­molecular π–π inter­actions [centroid–centroid distances = 3.583 (2)–3.782 (2) Å].

In the title compound, C21H15NO3S, the sulfonyl-bound phenyl ring forms a dihedral angle of 86.28 (5)° with the indole ring system. The mol­ecular structure is stabilized by intra­molecular C—H⋯O hydrogen bonds. The crystal packing is stabilized by weak inter­molecular C—H⋯O and C—H⋯π inter­actions.