A complex of formula [{CuCl{H 2 C(3,5‐Me 2 pz)}} 2 (µ‐Cl) 2 ] ( 1 ) is obtained and its structure is determined by single‐crystal X‐ray diffraction crystallography, revealing dinuclear character supporting a (CuN 2 Cl 2 ) 2 core. Compound 1 undergoes water dissociation that generates a change in the coordination sphere of the metals, yielding a mononuclear Cu II complex of the formula [CuCl{H 2 C(3,5‐Me 2 pz) 2 } 2 ]Cl · 3H 2 O ( 2 ), as supported by LeBail analysis and visible absorption spectroscopy. Interestingly, the optical features of 1 unravel characteristic patterns in the absorption spectrum, attributed solely to the formation of the (CuN 2 Cl 2 ) 2 core. The study of the magnetic properties of 1 reveals weak antiferromagnetic exchange coupling between the two Cu II ions that is transmitted through the double‐chloro bridge, which is supported by broken‐symmetry DFT calculations.