In this study, we focused on Au13 clusters with phosphine ligands and chlorine or acetylide as the coordinating ligands, [Au13(dppe)5X2] 3+ (X = Cl or acetylide) to investigate: (1) the behavior of ligand exchange reactions and (2) the development of selective and efficient methods for the formation of dimers using Au13 clusters. The following key findings were obtained. (1) Under certain conditions, Au13 clusters with Cl -as a counteranion can undergo a transformation where Cl -no longer acts as the counteranion but instead directly binds to the Au13 surface as a coordinating ligand. (2) The introduction of two types of ligands-chelating ligands that can complex and end-cap ligands that can suppress polymerizationresulted in the development of building block clusters that were programmed to form dimers consisting of two Au13 clusters. By applying Fe 2+ ions to these designed building block clusters, the formation of Au13 dimers was actually achieved. Furthermore, these dimers, having a charge donor and acceptor chemically bound together, displayed a higher rate constant for light-induced charge transfer than typical endothermic complexes. Future studies are expected to further investigate the new properties caused by dimerization.