In 1,8-dibenzoyl-2,7-di­phen­oxy­naphthalene, the planes of the benzene rings of the four naphthalene substituents are almost perpendicular to that of the naphthalene core.

In the molecule of (2,7-dimethoxynaphthalen-1-yl)(3-fluorophenyl)methanone, C19H15FO3, (I), the dihedral angle between the plane of the naphthalene ring system and that of the benzene ring is 85.90 (5)°. The molecules exhibit axial chirality, with either an R- or an S-stereogenic axis. In the crystal structure, each enantiomer is stacked into a columnar structure and the columns are arranged alternately to form a stripe structure. A pair of (methoxy)C-H...F hydrogen bonds and π-π interactions between the benzene rings of the aroyl groups link an R- and an S-isomer to form a dimeric pair. These dimeric pairs are piled up in a columnar fashion through (benzene)C-H...O=C and (benzene)C-H...OCH3 hydrogen bonds. The analogous 1-benzoylated compound, namely (2,7-dimethoxynaphthalen-1-yl)(phenyl)methanone [Kato et al. (2010). Acta Cryst. E66, o2659], (II), affords three independent molecules having slightly different dihedral angles between the benzene and naphthalene rings. The three independent molecules form separate columns and the three types of column are connected to each other via two C-H...OCH3 hydrogen bonds and one C-H...O=C hydrogen bond. Two of the three columns are formed by the same enantiomeric isomer, whereas the remaining column consists of the counterpart isomer. In the case of the fluorinated 1-benzoylated naphthalene analogue, namely (2,7-dimethoxynaphthalen-1-yl)(4-fluorophenyl)methanone [Watanabe et al. (2011). Acta Cryst. E67, o1466], (III), the molecular packing is similar to that of (I), i.e. it consists of stripes of R- and S-enantiomeric columns. A pair of C-H...F hydrogen bonds between R- and S-isomers, and C-H...O=C hydrogen bonds between R(or S)-isomers, are also observed. Consequently, the stripe structure is apparently induced by the formation of R...S dimeric pairs stacked in a columnar fashion. The pair of C-H...F hydrogen bonds effectively stabilizes the dimeric pair of R- and S-enantiomers. In addition, the co-existence of C-H...F and C-H...O=C hydrogen bonds makes possible the formation of a structure with just one independent molecule.

The asymmetric unit of the compound contains two independent conformers. Each conformer is stacked along the a axis to form columns through van der Waals inter­actions only.

The title compound, C24H16O4, crystallized with two independent molecules in the asymmetric unit. Both carbonyl groups in these molecules form intramolecular O-H...O=C hydrogen bonds with neighbouring hydroxy groups, affording six-membered cyclic structures. In the crystal, dimeric aggregates arise from two intermolecular O-H···O=C hydrogen bonds between both independent molecules, forming head-to-tail square-shaped cyclic ···O···H···O···H··· hydrogen bonds. These dimeric aggregates are connected into layers in the bc plane by intermolecular (naphthalene)C-H...O=C interactions. On the other hand, the analogous compound bearing methoxy groups at the 2- and 7-positions of the naphthalene ring, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene [Nakaema et al. (2008). Acta Cryst. E64, o807], forms a three-dimensional molecular network via C-H···O=C and π-π interactions between the benzoyl groups. These results show that the intramolecular O-HvO=C hydrogen bonds in the title compound control the orientations of the benzoyl groups and thus promote the formation of the cyclic intermolecular O-H···O=C interactions involving the same donor and acceptor groups in pairs of molecules.

The title compound possesses crystallographically imposed twofold symmetry with two C atoms lying on the rotation axis and has a non-coplanarly accumulated aromatic-rings structure. In the crystal, C—H⋯O=C hydrogen bonds between the benzene rings and the carbonyl groups and C—H⋯O=N hydrogen bonds between the benzene rings and the nitro groups are observed; these C—H⋯O hydrogen bonds link the mol­ecules, forming a three-dimensional structure.