Established less than a decade ago, the fascinating field of two-dimensional (2D) soft materials is advancing continuously towards widespread recognition. After demonstrating the feasibility of obtaining nano-thin supramolecular sheets and morphologically related tubular objects, considerable efforts are being undertaken to explore the functional potential of soft nanosheets. Self-assembly is a major tool for the controlled formation of nanometre-sized 2D objects. In this account, we share our current understanding of the structural requirements to direct the self-assembly of water-soluble, negatively charged oligomers in 2D. The discussion covers some promising areas of utilization such as the reporting of weak mechanical perturbations, the assembly of lightharvesting antennae, the transfer of excitation energy and the polymerization of pre-organized assemblies. The systems presented in this work illustrate the potential of 2D supramolecular materials as complementary systems to their covalent counterparts.