Single-metal-ion-based rigid molecular building blocks (MBBs) have been utilized to design and synthesize novel metal−organic assemblies. Reaction between In(NO3)3·2H2O and 2,5-pyridinedicarboxylic acid (2,5-H2PDC) has permitted the assembly of two supramolecular isomers, a Kagomé lattice and an unprecedented M6L12 discrete octahedron.