Given the importance of structural precision, we envisioned the use of metal-organic frameworks (MOFs) as a new platform for the construction of bifunctional acid-base active sites (Fig. ). The synthesis of Brønsted acid-base MOFs has received far less attention than its closely related counterpart, bifunctional Lewis acid-base MOFs. While several examples of frameworks jointly functionalized with amine and sulfonic acid groups have been reported, to our knowledge only one previous study has demonstrated the colocalization of carboxylic acids and amines in a single MOF pore. In this prior work, the functional groups were postsynthetically incorporated in a single crystal-to-single crystal fashion using sequential linker installation. As this technique is specific to PCN-700, a zirconium-based framework containing an ordered array of missing linkers, this study gained active site precision at the cost of generalizability and chemical tunability.