In the title mononuclear complex, [Cu(C₁₁H₇O₂)(NO₃)(C₁₀H₈N₂)], the Cu^II atom is five-coordinated in a distorted square-pyramidal environment by two N atoms of 2,2′-bipyridine, two O atoms of 1-formyl-2-naphtholate and a nitrate O atom. Mol­ecules are stacked by π–π inter­actions [the dihedral angle, interplanar average distance and ring-centroid separation involved in stacking are 0.000 (1), 3.3504 (2) and 4.0800 (7) Å for stronger inter­actions, and 2.505 (1), 3.5373 (2) and 4.2048 (9) Å for weaker inter­actions] into a one-dimensional structure.

The title compound, [ZnCl₂(C₂₁H₁₅N₃)], was obtained from the reaction of ZnCl₂·4H₂O with 4′-phenyl­terpyridine (L) and disodium 2,6-dipicolinate. The Zn²⁺ cation is ligated by the N atoms of the tridentate L ligand and two chloride anions, forming a ZnN₃Cl₂ polyhedron with a distorted trigonal–bipyramidal coordination geometry. In the crystal, nonclassical C—HCl hydrogen bonds are observed.

The title salt, [K₂(C₁₆H₁₂O₆)]_n, was obtained by the reaction of 1,2-bis­[4-(ethyl-carbox­yl)-phenox­yl]ethane with KOH in water. The anion lies on a crystallographic inversion center, which is located at the mid-point of the central C—C bond. The K⁺ cation is coordinated by six O atoms, two from the chelating carboxyl­ate group of the anion and four from four neighboring and monodentately binding anions, giving rise to an irregular [KO₆] coordination polyhedron. The coordination mode of the cation leads to the formation of K/O layers parallel to (100). These layers are linked by the nearly coplanar anions (r.m.s. deviation of 0.064 Å of the carboxyl, aryl and O—CH₂ groups from the least-squares plane) into a three-dimentional network.

In the title compound, C₂₂H₁₈N₄·2H₂O, the organic fragment lies across a centre of inversion in the P2₁/n space group. The water mol­ecules form C(2)-type hydrogen-bonded chains which are linked to the 1,4-bis­(1H-benzimidazol-1-yl­methyl)­benzene mol­ecules through O—HN hydrogen bonds, forming sheets reinforced by π–π stacking inter­actions between the aromatic rings within the layers.