The three title compounds, namely 4-phenyl-1H-imidazolium hexa-μ₂-chloro-chloro-μ₄-oxo-tris(4-phenyl-1H-imidazole-κN¹)tetracopper(II) monohydrate, (C₉H₉N₂)[Cu₄Cl₇O(C₉H₈N₂)₃]·H₂O, hexa-μ₂-chloro-μ₄-oxo-tetrakis(pyridine N-oxide-κO)tetracopper(II), [Cu₄Cl₆O(C₅H₅NO)₄], and hexa-μ₂-chloro-tetrakis(2-methyl-1H-imidazole-κN¹)-μ₄-oxo-tetracopper(II) methanol trisolvate, [Cu₄Cl₆O(C₄H₆N₂)₄]·3CH₄O, exhibit the same Cu₄OCl₆ framework, where the O atom at the centre of an almost regular tetrahedron bridges four copper cations at the corners. This group is in turn surrounded by a Cl₆ octahedron, leading to a rather globular species. This special arrangement of the Cu^II cations results in a diversity of magnetic behaviours.