Supramolecular co-ordination polymers are formed in organic solvents by metal-directed self-assembly using 1:1 mixtures of (dppp)M(OTf)2 complexes (M = Pd(II) or Pt(II), dppp = bis-(diphenylphosphino)- propane, OTf = triflate) and a non-linear bidentate dipyridyl-substituted ligand. In aqueous methanol solutions, hollow metallo-supramolecular vesicles and smaller, completely filled nanospheres form.