A self-assembled coordination cage usually possesses one well-defined three-dimensional (3D) cavity whereas infinite number of 3D-cavities are crafted in a designer metal-organic framework. Construction of a discrete coordination cage possessing multiple number of 3D-cavities is a challenging task. Here we report the peripheral decoration of a trinuclear [Pd₃L₆] core with one, two and three units of a [Pd₂L₄] entity for the preparation of multi-3D-cavity conjoined-cages of [Pd₄(L^a)₂(L^b)₄], [Pd₅(L^b)₄(L^c)₂] and [Pd₆(L^c)₆] formulations, respectively. Formation of the tetranuclear and pentanuclear complexes is attributed to the favorable integrative self-sorting of the participating components. Cage-fusion reactions and ligand-displacement-induced cage-to-cage transformation reactions are carried out using appropriately chosen ligand components and cages prepared in this work. The smaller [Pd₂L₄] cavity selectively binds one unit of NO₃⁻, F⁻, Cl⁻ or Br⁻ while the larger [Pd₃L₆] cavity accommodates up to four DMSO molecules. Designing aspects of our conjoined-cages possess enough potential to inspire construction of exotic molecular architectures.

Mimicking biological structures such as fruits and seeds using molecules and molecular assemblies is a great synthetic challenge. Here we report peanut-shaped nanostructures comprising two fullerene molecules fully surrounded by a dumbbell-like polyaromatic shell. The shell derives from a molecular double capsule composed of four W-shaped polyaromatic ligands and three metal ions. Mixing the double capsule with various fullerenes (that is, C₆₀, C₇₀ and Sc₃N@C₈₀) gives rise to the artificial peanuts with lengths of ∼3 nm in quantitative yields through the release of the single metal ion. The rational use of both metal–ligand coordination bonds and aromatic–aromatic π-stacking interactions as orthogonal chemical glue is essential for the facile preparation of the multicomponent, biomimetic nanoarchitectures.

Complexation of the ligand 1 with Pd(NO₃)₂ leads to the self-assembly of a very stable M₂L₄ type macrotricyclic cage that encapsulates a nitrate ion inside its cavity.