Two　types　of　palladium(II)-based　metallacalixarenes　[ML](2+)　and　[ML2](2+)　have　been　synthesized　through　coordination-driven　self-assembly　from　a　series　of　flexible　pyridine-bridged　diimidazole　ligands　[2,6-bis　((1H-imidazol-1-yl)methyl)　pyridine　(L-1),　2,6-bis((1H-benzo[d]imidazol-1-yl)methyl)pyridine　(L-2),　2,6-bis((1H-naphtho[2,　3-d]imidazol-1-yl)methyl)pyridine　(L-3)],　with　palladium(II)-based　building　blocks　[Pd(BF4)(2)(M-1-BF4)　and　(tmeda)Pd(NO3)(2)(M-2-NO3)　(tmeda　=　N,N,N＇,N＇-tetramethyl-ethylenediamine)].　All　complexes　were　characterized　by　NMR　spectroscopy　(H-1　NMR　and　C-13　NMR),　mass　spectrometry　(CSIMS,　ESI-HRMS)　and　elemental　analysis.　The　single　crystal　X-ray　diffraction　analysis　of　[(ML22)-L-1](NO3)(2),　[(ML23)-L-1](NO3)(2),　[(ML23)-L-1](PF6)(2)　and　[(ML3)-L-2](NO3)(2)　further　confirmed　the　uniquely　single　bowl-shape　and　double　bowl-shape　structures.　The　anion　binding　properties　within　the　metallacalixarenes　as　receptors　were　also　investigated　by　NMR　titration　experiments　in　DMSO.　(C)　2020　Chinese　Chemical　Society　and　Institute　of　Materia　Medica,　Chinese　Academy　of　Medical　Sciences.　Published　by　Elsevier　B.V.　All　rights　reserved.