The development of novel building blocks which are capable to self-assemble and the design of artificial receptors for a given substrate are two main goals in supramolecular chemistry. Herein, we describe the synthesis and evaluation of a de novo designed new binding motif for carboxylates in polar solution, the guanidiniocarbonyl pyrroles. The thermodynamic properties of this new receptor class were intensively studied both experimentally by NMR, X-ray and ESI MS, and theoretically using molecular modelling. These studies led to a detailled structural and thermodynamic understanding of the recognition event. Futhermore, a comparative thermodynamic study allowed us to arrive at a supramolecular structure-binding relationship (SSBR) for the complexation of carboxylates by this receptor class. Based on this novel recognition motif, new supramolecular structures can be designed. Self-complementary guanidiniocarbonyl pyrrole / carboxylate zwitterions form intramolecular loops, dimers or supramolecular oligomers depending on the molecular structure of the zwitterion and the experimental conditions. Guanidiniocarbonyl pyrrole cations can also be used as receptors for the side chain selective- and stereoselective complexation of amino acids in aqueous solvents. By incorporating such guanidiniocarbonyl pyrrole units into a combinatorial receptor library, one can also identify receptors for the effective complexation of biologically relevant oligopetides.