The assembly of atomically precise clusters into superstructures has tremendous potential in structural tunability and applications. Here, we report a series of single-cluster nanowires, single-cluster nanorings, and three-dimensional superstructure assemblies built by POM clusters. By stepwise tuning of interactions at molecular levels, the configurations can be varied from single-cluster nanowires to nanorings. A series of single-cluster nanostructures in different configurations can be achieved with up to 15 kinds of POM clusters. The single-cluster nanowires and three-dimensional superstructures perform enhanced activity in the catalytic and electrochemical sensing fields, illustrating the universal functionality of single-cluster assemblies.