The bis(anil) molecule of the title compound, C47H32N2O2.C6H4Cl2, contains two anil fragments in the enol-enol form, exhibiting intramolecular O-H…N hydrogen bonds. The two hydroxynaphthalene ring systems are approximately parallel to each other with a dihedral angle of 4.67 (8)◦ between them, and each ring system makes a large dihedral angle [55.11 (11) and 48.50 (10)◦] with the adjacent benzene ring. In the crystal, the bis(anil) molecules form an inversion dimer by a pair of weak C-H…O interactions. The dimers arrange in a one-dimensional column along the b axis via another C-H…O interaction and a π-π stacking interaction between the hydroxynaphthalene ring system with a centroid-centroid distance of 3.6562 (16) Å. The solvent 1,2-dichlorobenzene molecules are located between the dimers and bind neighbouring columns by weak C-H…Cl interactions. Theoretical prediction of potential biological activities was performed, which suggested that the title anil compound can exhibit histone deacetylase SIRT2, histone deacetylase class III and histone deacetylase SIRT1 activities, and will act as inhibitor to aspulvinone dimethylallyltransferase, dehydro-l-gulonate decarboxylase and glutathione thiolesterase. © 2020 International Union of Crystallography. All rights reserved.