The molecular structures of six two-component molecular crystals using chloronitrobenzoic acids and 4-benzoylpyridine as components were characterized by a combination of techniques: solution NMR, solid-state IR spectra, differential scanning calorimetry (DSC) and single-crystal X-ray crystallography. The X-ray analysis revealed that the brief alternation of substituents in acid components greatly affected the packing modes of molecular crystals, and that the weaker intermolecular interactions such as C-H...O hydrogen bondings and pi-pi stacking interactions play a significant role in determining the packing modes of molecular crystals. (C) 2002 Elsevier Science B.V. All rights reserved.