all the complexes, ligands H2L or (HL)− acting as helicands chelated metal ions to form uniquely tetrahedral helicate units which further assembled into meso-metallosupermolecules with various architectures, such as layer structures in 1 and 4, three-dimensional CdSO4-like framework in 2, and double-layered framework in 3. Those tetrahedral helicate units not only serve as intriguingly versatile supramolecular