Antimony(III) alkoxide cages were designed as building blocks for predictable supramolecular self-assembly. Supramolecular synthons featuring two Sb...O secondary bonding interactions (SBIs), each SBI stronger than 30 kJ/mol, were used to drive the formation of the supramolecular architectures. Judicious choice of pendant groups provided predictable control over the formation of self-assembled 3D columnar helices, which crystallized with hollow morphologies, or a self-assembled 2D bilayer. The Sb...O stretching frequency provides a spectroscopic signature of Sb...O SBI formation.