Abstract Various 1,2-benzoquinone dioximes (bqdH) have been combined with CuCl2 or CuBr2 to afford the following new dimeric adducts: di-μ-chlorobis[chloro(1,2-benzoquinone dioxime)copper(II)], [CuCl2(bqdH)]2; di-μ-chlorobis[chloro(4-chloro-1,2-benzoquinone dioxime)copper(II)], [CuCl2(ClbqdH)]2; di-μ-chlorobis[chloro(4-methyl-1,2-benzoquinone dioxime)copper(II)], [CuCl2(MebqdH)]2; di-μ-chlorobis[chloro(4,5-dimethyl-1,2-benzoquinone dioxime)copper(II)], [CuCl2(Me2bqdH)]2; di-μ-bromobis[bromo(1,2-benzoquinone dioxime)copper(II)], [CuBr2(bqdH)]2; di-μ-bromobis[bromo(4-chloro-1,2-benzoquinone dioxime)copper(II)], [CuBr2(ClbqdH)]2; di-μ-bromobis[bromo(4,5-dimethyl-1,2-benzoquinone dioxime)copper(II)], [CuBr2(Me2bqdH)]2. These brown solids were characterized by variable-temperature magnetic susceptibility measured within 4.2–300 K, as well as by room temperature near infrared and electron spin resonance spectra from which the dimeric structure of the compounds was inferred. The intradimer magnetic exchange interaction was found to occur by a super exchange mechanism mediated by the valence p wave functions of the bridging halide ions. It was observed that the electrophilic character of the benzoquinonoid ligands affects the magnetic exchange via backbonding and through mesomeric π electron delocalization. It was found, most interestingly, that the tendency to ferromagnetic exchange interaction within a dimer is the stronger, the more electrophilic the bqdH ligands can be made.