Self‐assembled coordination cages and metal–organic frameworks have relied extensively on symmetric ligands in their formation. Here we have prepared a relatively simple system employing an unsymmetric ligand that results in two distinct self‐assembled structures, a [Fe2L3]4+ helicate and a [Fe4L6]8+ cage composed of 10 interconverting diastereomers and their enantiomers. We show that the steric profile of the ligand controls the complexity, thermodynamics and kinetics of interconversion of the system. [ABSTRACT FROM AUTHOR]