The nonadentate podands L7, L8 et L9 have been prepared according to a multi-step strategy using the flexible 3-(2-hydroxy-ethyl)-pentane-1,5-diol, 4-(3-hydroxy-propyl)-heptane-1,7-diol and 3-(2-hydroxy-ethyl)-3-methyl-pentane-1,5-diol covalent tripods, respectively. Minor changes in the structure of the ligands, i.e. the replacement of the apical hydrogen atom with a methyl group, or the introduction of an extra methylene in the caping moiety, induce dramatic effects in the structures of the resulting lanthanide complexes [Ln(Lx)]3+ (x = 7–9). The complexes [Ln(L7)]3+ and [Ln(L9)]3+ exist as mixtures of two endo isomers which do not interconvert on the NMR time scale, whereas [Ln(L8)]3+ exhibits a single exo isomer.