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• 4′-functionalized 2,2′:6′,2″-terpyridine derivatives have been synthesized and structurally characterized. • Supramolecular self-assembly of the X-ray structures are explored in detail in the context of crystal engineering. • Quantification of noncovalent interactions through Hirshfeld surface analysis. • Bader's theory of 'atoms-in-molecules'(AIM) have been performed to characterize the noncovalent interactions. • Theoretical 'Noncovalent Interaction' (NCI) plot index have been used to characterize the interactions that are involved within the structures. Three versatile 4′-substituted 2,2′:6′,2″-terpyridine compounds (1 – 3) having different substitutions (4-ethoxyphenyl, 4-methoxyphenyl and pyridyl) at 4′-position of the central pyridine ring have been synthesized and structurally characterized. Three representative crystal structures have been determined through single crystal X-ray diffraction analysis. X-ray crystallography revels that the structures are stabilized through C–H···π and π–π stacking interactions. In the solid-state, the supramolecular assemblies of the title compounds have been explored in detail. Compounds (1) and (3) exhibits both C–H···π and π–π interactions in building supramolecular assemblies whereas compound (2) exhibit π–π interaction only. All the intermolecular interactions that are involved within the structures are quantified through Hirshfeld surface analyses. The weak noncovalent interactions that played significant role in building supramolecular assemblies are further characterized by Bader's theory of 'atoms-in-molecules' (AIM). Finally, the supramolecular networks are characterized by theoretical 'Noncovalent Interaction' (NCI) plot index. The supramolecular solid-state frameworks of three 4′-functionalized 2,2′:6′,2″-terpyridine derivatives have been quantified which are further characterized theoretically by the Bader's theory of 'atoms-in-molecules'(AIM) and 'noncovalent interaction' (NCI) plot index. Image, graphical abstract [ABSTRACT FROM AUTHOR]

· Newer ninhydrin derivatives have been studied. • Supramolecular self-assembly of the X-ray structure were explored in detail. • Hirshfeld surface and Energy framework analysis were performed. • DFT calculation were performed to explore the energetic features. • Bader's theory of "atoms-in-molecules" (AIM) have been performed. Three ninhydrin derivatives (2 – 4) have been synthesized where the reaction of ninhydrin with Meldrum's acid yielded [3.3.3] propellanoid (2) and ethyl 2,2-bis (1,3-dioxo-2,3-dihydro-1 H -inden-2-yl)acetate (3) while with malononitrile yielded a spiroindenopyran (4). The products being crystalline in nature and are characterized by single crystal X-ray diffraction in addition to other spectroscopic studies. X-ray crystallography reveals that solid-state structure of the title compounds exhibits C‒H···π, π‒π and lone-pair(l.p)···π interactions in building supramolecular assemblies. Indeed, compound (2) was stabilized through extended supramolecular C‒H···π/π‒π/π···H‒C network whereas compounds (3) and (4) are stabilized through lone-pair (l.p)···π and π‒π interaction respectively. The diverse intermolecular interactions via Hirshfeld surface analysis enables quantitative contributions to the crystal packing that exposes the similarities and differences in the interactions experienced by each compound. The distinctive energy frameworks have been calculated for individual molecules and the interaction energies suggest that the contacts are largely dispersive in nature. The binding energies associated with the non-covalent interactions observed in the crystal structures have been calculated using theoretical DFT calculations. Finally, the interplay between the interactions have been characterized by Bader's theory of "atoms-in-molecules" (AIM). Image, graphical abstract [ABSTRACT FROM AUTHOR]