With aromatic and aliphatic thiol-S donor Schiff base ligands, the copper− sulfur clusters, [(L1) 8 Cu I 6 Cu II 2 ](ClO 4 ) 2 •DMF•0.5CH 3 OH (1) and [(L2) 12 Cu I 5 Cu II 11 (μ 4 -S)(μ 4 -O) 6 ](ClO 4 )•4H 2 O, respectively, have been reported (Chem. Commun. 2017, 53, 3334); HL1/HL2 are 2-(((3-methylthiophen-2-yl)methylene)amino)benzene/ethanethiol). Complex 1 comprises a wheel shaped Cu 8 S 8 framework, made up of interlinked Cu 2 {μ-S(R)} 2 units. To understand the properties with relevance to the Cu A site and to check whether self-assembly generates similar type clusters to 1, three complexes, [(L3) 8 Cu I 6 Cu II 2 ](ClO 4 ) 2 •(C 2 H 5 ) 2 O•2.5H 2 O (2), [(L3 Cl ) 8 Cu I 6 Cu II 2 ](ClO 4 ) 2 •1.25-(C 2 H 5 ) 2 O•1.25CH 3 OH•2H 2 O (3), and [(L3 CF3 ) 8 Cu I 6 Cu II 2 ](ClO 4 ) 2 •2(C 2 H 5 ) 2 O•H 2 O (4) have been synthesized with supporting ligands HL3 X (HL3 = 2-((furan-2-ylmethylene)amino)benzenethiol when X = −H; X = −Cl or −CF 3 para to thiol-S are HL3 Cl and HL3 CF3 ligands, respectively). The X-ray structures of 3 and 4 feature a similar Cu 8 S 8 architecture to 1. The spectroscopic properties and the X-ray structures revealed that 2−4 are fully spin delocalized mixed valence (MV) of class-III type clusters. The structural parameters of the N 2 Cu 2 {μ-S(R)} 2 units of 3 and 4 closely resemble those of the MV binuclear Cu A site. With the aid of UV−vis-NIR, EPR, and spectroelectrochemical studies, the electronic properties of these complexes have been described in comparison with the MV model complexes and Cu A site.