Abstract: | In the two title copper(II) complexes, CuL(C5H7O2)]n, (I), and CuL′(C5H7O2)], (II), respectively, where HL is 4‐hydroxy‐3‐methoxybenzaldehyde picoloylhydrazone, C14H12N3O3, and HL′ is 4‐methoxybenzaldehyde picoloylhydrazone, C14H12N3O2, the CuII ions display a highly Jahn–Teller‐distorted octahedral and a square‐planar coordination geometry, respectively. In complex (I), two neighbouring CuII atoms are bridged by L? and acetylacetonate, alternately, giving rise to a one‐dimensional chain of CuN2O4 octahedra interconnected by these two ligands along the a axis. In addition, the hydroxy H atom of the vanillin group connects to the carboxyl O atom of the adjacent chain via an O—H...O hydrogen bond, giving rise to a three‐dimensional supramolecular assembly. Complex (II) displays a discrete structure. |