Aromatic carboxylic anhydrides are ubiquitous building blocks in organic materials chemistry and have received considerable attention in the synthesis of organic semiconductors, pigments, and battery electrode materials. Here we extend the family of aromatic carboxylic anhydrides with a unique new member, a conjugated cyclophane with four anhydride groups. The cyclophane is obtained in a three‐step synthesis and can be functionalised efficiently, as shown by the conversion into tetraimides and an octacarboxylate. Crystal structures reveal the high degree of porosity achievable with the new building block. Excellent electrochemical properties and reversible reduction to the tetraanions are shown for the imides; NMR and EPR measurements confirm the global aromaticity of the dianions and evidence the global Baird aromaticity of the tetraanions. Considering the short synthesis and unique properties, we expect widespread use of the new building block in the development of organic materials. A unique new member of the family of aromatic carboxylic anhydride building blocks—a conjugated square‐shaped cyclophane with four anhydride groups—is presented. The building block can be obtained in a three‐step synthesis and functionalised efficiently to give materials with highly interesting properties ranging from high degrees of porosity to excellent electrochemical properties, as shown by the conversion into imides and carboxylates.