| Summary: | Three functionalized chalcones containing combinations of nitro functional groups have been synthesized via Claisen-Schmidt condensation between 2-nitroacetophenone and nitrobenzaldehyde, and the crystal structures obtained ((<i>E</i>)-1,3-bis(2-nitrophenyl)prop-2-en-1-one, <b>1a</b>, (<i>E</i>)-1-(2-nitrophenyl)-3-(3-nitrophenyl)prop-2-en-1-one, <b>1b</b> and (<i>E</i>)-1-(2-nitrophenyl)-3-(4-nitrophenyl)prop-2-en-1-one, <b>1c</b>), C<sub>15</sub>H<sub>10</sub>N<sub>2</sub>O<sub>5,</sub> are reported. Compounds <b>1a</b> and <b>1c</b> crystallized in the triclinic centrosymmetric space group <i>P</i><inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mover accent="true"><mn>1</mn><mo>¯</mo></mover></semantics></math></inline-formula>, whereas compound <b>1b</b> crystallized in the orthorhombic space group <i>Pbca</i>. The X-ray analysis reveals that structures <b>1a</b> and <b>1b</b> exhibits <i>s</i>-<i>trans</i> conformation, whereas structure <b>1c</b> exists in <i>s</i>-<i>cis</i> conformation, concerning the olefinic double bonds. In addition, the results show that the position of the nitro substituent attached to the aromatic B-ring has a direct effect on the molecular coplanarity of these compounds. The Hirshfeld surface analysis suggests that the non-covalent π-π stacking interactions are the most important contributors for the crystal packing of <b>1a</b> and <b>1b</b>. In <b>1c</b>, the crystal packing is mainly stabilized by weak intermolecular C―H···O interactions due to the planar nature of the molecule.
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