Crystal Structures and Intermolecular Interaction Networks of Forms I–III of 2-Chloro-5-nitrotoluene

Comparison of the newly determined structures of Forms II and III with the previously reported Form I reveals closely similar, essentially planar molecular conformations across the three crystal forms. Hirshfeld surface analysis showed broadly related intermolecular-contact environments, while detailed structural analysis revealed differences in the geometry, connectivity, and long-range propagation of the local motifs. All polymorphs contain centrosymmetric C–H···O-associated dimers and slipped π···π stacking, whereas Forms I and III additionally incorporate a directional C–Cl···O contact into its supramolecular network. Intermolecular-energy calculations showed that the strongest representative molecular pairs in the three forms are comparable in magnitude and largely dispersion-driven, while the pair containing the C–Cl···O contact is energetically modest. Energy-framework analysis further revealed distinct spatial organizations of the dominant energetic pathways. These results indicate that the polymorphic distinction between Forms I–III is best understood as a packing-driven reorganization of related intermolecular interactions into different long-range supramolecular and energetic networks.