Five new cyclic peptoids containing (2S,4R)-4-hydroxyproline (Hyp) residues have been designed and synthesized using a mixed “submonomer/monomer” approach. Metal cations’ affinities and ion transport activities have been assessed by experimental (NMR and HPTS assay in liposomes) and computational methods. Easy functionalization of proline residues’ hydroxy groups afforded a bouquet of cyclic oligomers showing correlation between ion transport abilities and cytotoxic activities.
