Supramolecular chemistry is "the chemistry beyond the covalent bond". Advance of supramolecular chemistry "call" for additional analytical methods to better characterize the obtained structure in solution. This "call" is even more pronounced for labile dynamic multi-component systems. For more than a decade now we have been using diffusion NMR to probe supramolecular systems both in organic solvents and in aqueous solutions. In the past we have used diffusion NMR to study, inter alia, crown-ethers, cryptands and CD complexes, CD based rotaxanes, rosettes and dimeric capsules of tetraureacalix[4]arenes. Recently we have used this approach to probe the structure of hydrogen-bound supramolecular polymers in solution and to study the structure of porphyrin-calixarene assemblies. Complexes of cucurbituril CB[n] with different guests were also studied very recently with diffusion NMR. We also demonstrated that diffusion NMR is an extremely useful methodology to probe encapsulation in a series of tetraureacalix[4]arenes dimers.