Consideration of the crystal structures of four new 2,2′;6′,2″-terpyridine derivatives in terms of the weaklattice interactions which can be discerned through calculation of their Hirshfeld surfaces shows that despitethe common feature of stacking of the near-planar aromatic entities, specific interactions beyond dispersionwithin the stacked arrays are relatively uncommon. This is in accord with what is seen in the sameanalysis of the structures of known analogues, which provides context for the present work. That this is notsimply a consequence of the transoid array of the N-donors in these free ligands is seen from extension ofthe Hirshfeld surface analysis to the structures of protonated species where cisoid arrays are seen