In the present study, we developed an alternative approach that focuses on driving the formation of oligomers through simple coordination between chelating ligands and transition metal ions. By introducing chelating ligands to the Au cluster surface and endcapping ligands to suppress polymerization, we developed building block molecules programmed to self-assemble into dimers upon the addition of metal ions (Scheme 1C). Indeed, the designed building block clusters efficiently formed stable dimers consisting of two Au clusters in the presence of iron ions. Furthermore, the dimers have been shown to exhibit photo-induced charge transfer property.