43,44,47,48‐Tetrathiaoctaphyrin(2.1.1.1.2.1.1.1) and its Organometallic bis‐Rh III Complex: Coordination‐Driven Switching of Conformation and Aromaticity

43,44,47,48‐Tetrathiaoctaphyrin (2.1.1.1.2.1.1.1), obtained in a concise synthesis, is found to adopt a C 2 ‐symmetric figure‐eight conformation in solution and in the solid state. The macrocycle is globally nonaromatic but exhibits strong absorption in the visible and near‐infrared regions. Metalation of the octaphyrin with Rh I (CO) 2 Cl 2 produced an unprecedented dinuclear complex featuring two octahedral Rh(III) centers and four RhC bonds. The latter species is globally aromatic and has a distinct, quasi‐rectangular shape. Using an in‐depth NMR and computational analysis, the Rh 2 complex is found to exhibit an unusual case of isomerism resulting from the combined effect of local helicity, conformationally locked trans ‐vinylene bridges, and polar axial ligation.