The in-situ formed hydrazone Schiff base ligand (E)-N′-(2-oxy-3-methoxybenzylidene)benzohydrazide (L 2− ) reacts with copper(II) acetate to a tetranuclear open cubane [Cu(L)] 4 complex which crystallizes as two symmetry-independent (Z′=2) S 4 -symmetrical molecules in different twofold special positions with a homodromic water tetramer. The two independent (A and B) open- or pseudo-cubanes with Cu 4 O 4 cores of 4+2 class (Ruiz classification) each have three different magnetic exchange pathways leading to an overall antiferromagnetic coupling with J 1B =J 2B =−17.2cm −1 , J 1A =−36.7cm −1 , J 2A =−159cm −1 , J 3A =J 3B =33.5cm −1 , g=2.40 and ρ=0.0687. The magnetic properties have been analysed using the H=−Σ i , j J ij (S i S j ) spin Hamiltonian.