Controlling the properties of self-assembled supramolecules via intrinsic parameters (i.e., structural information in the subunits) enables the reliable construction of assemblies of well-defined size and composition. Here we show that an optimum balance between repulsive (e.g., steric) and attractive (e.g., pi-pi, dipole-dipole) noncovalent interactions between subunits of a lipophilic 8-(3-pyridyl)-2'-deoxyguanosine derivative enables the high fidelity formation of a stable and discrete self-assembled dodecamer. In contrast, the isosteric 8-phenyl-2'-deoxyguanosine derivative assembles into an octamer because it cannot engage in additional dipole-dipole interactions. Adding dodecamers to a supramolecular construction toolbox, already containing octamers and hexadecamers made from other 8-aryl-2'-deoxyguanosine derivatives, should enable the preparation of a wide variety of self-assembled nanostructures where the size and the number of functional elements can be precisely fine-tuned for specific applications.