Steric repulsion and supramolecular assemblies <i>via</i> a two-dimensional plate by C—H...O hydrogen bonds in two closely related 2-(benzofuran-2-yl)-2-oxoethyl benzoates

2-(Benzofuran-2-yl)-2-oxoethyl 2-chlorobenzoate, C₁₇H₁₁ClO₄ (I), and 2-(benzofuran-2-yl)-2-oxoethyl 2-methoxybenzoate, C₁₈H₁₄O₅ (II), were synthesized under mild conditions. Their chemical and molecular structures were analyzed by spectroscopic and single-crystal X-ray diffraction studies, respectively. These compounds possess different <i>ortho</i>-substituted functional groups on their phenyl rings, thus experiencing extra steric repulsion force within their molecules as the substituent changes from 2-chloro (I) to 2-methoxy (II). The crystal packing of compound (I) depends on weak intermolecular hydrogen bonds and π–π interactions. Molecules are related by inversion into centrosymmetric dimers <i>via</i> C—H...O hydrogen bonds, and further strengthened by π–π interactions between furan rings. Conversely, molecules in compound (II) are linked into alternating dimeric chains propagating along the [101] direction, which develop into a two-dimensional plate through extensive intermolecular hydrogen bonds. These plates are further stabilized by π–π and C—H...π interactions.