Re‐discovery: The only rhenium(VII)–chlorine compound known previously was ReO3Cl, and chloride oxides of composition AO2Cl3 (A=nonmetal or metal) were completely unknown. The synthesis of ReO2Cl3 has now been achieved. The compound exists as a chlorine‐bridged dimer (see Figure; Re red, O blue, Cl green) in the solid state, and as a monomer in solution.