Two isostructural 3d-4f compounds with the common formula [Ln2Ni2(SC4AS)2(H2O)6(phen)4]·[Ni(phen)3]2·[Ni(H2O)6]·8H2O (Ln=Er (CIAC-216) and Nd (CIAC-217); H4SC4AS=sulfonylcalix[4]arenetetrasulfonate; phen=1,10-phenanthroline) were synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals these two compounds exhibit three-dimensional (3D) supramolecular structures in which the heterometallic [Ln2Ni2(SC4AS)2(H2O)6(phen)4]6− units are linked together through π⋯π interactions between phen ligands into a 1D supramolecular chain and further interconnected through hydrogen bonds with [Ni(H2O)6]2+ cations. The calixarene conformation and magnetic properties of both compounds were also discussed.