Charge‐separated metal–organic frameworks (MOFs) are a unique class of MOFs that can possess added properties originating from the exposed ionic species. A new charge‐separated MOF, namely, UNM‐6 synthesized from a tetrahedral borate ligand and Co²⁺ cation is reported herein. UNM‐6 crystalizes into the highly symmetric P43n space group with fourfold interpenetration, despite the stoichiometric imbalance between the B and Co atoms, which also leads to loosely bound NO₃⁻ anions within the crystal structure. These NO₃⁻ ions can be quantitatively exchanged with various other anions, leading to Lewis acid (Co²⁺) and Lewis base (anions) pairs within the pores and potentially cooperative catalytic activities. For example, UNM‐6‐Br, the MOF after anion exchange with Br⁻ anions, displays high catalytic activity and stability in reactions of CO₂ chemical fixation into cyclic carbonates.