The enone group and the benzene rings of the title compound, C16H13NO4, are each planar. In the crystal structure, inter­molecular C—H⋯O inter­actions form chains along the a axis.

In the title compound, C17H13NO3, the dihedral angle between the benzene rings is 2.57 (4)°. The crystal structure is stabilized by C—H...O interactions, which form a three‐dimensional network, and by C—H...π interactions.

The title compound, C16H12Cl2O, exhibits second-order nonlinear optical properties as it crystallizes in a non-centrosymmetric space group. The dihedral angle between the benzene rings is 34.02 (6)°. Intermolecular C—H...O interactions link the molecules to form chains along the c axis.

In the title compound, C18H18O4, the dihedral angle between the benzene rings is 9.07 (7)°. Inter­molecular C—H⋯O inter­actions form chains along the c axis. The crystal structure is further stabilized by C—H⋯π inter­actions.

Key indicatorsSingle-crystal X-ray study T = 100 K Mean (C-C) = 0.002 Å R factor = 0.027 wR factor = 0.072 Data-to-parameter ratio = 43.8For details of how these key indicators were automatically derived from the article, see