The octanuclear iodine‐chlorine interhalides [I4Cl4]2− and [I3Cl5]2− were prepared in two steps. Firstly, addition of ICl to the triaminocyclopropenium chloride salt [C3(NEt2)3]Cl forms the trihalide ICl2− salt, secondly, addition of half an equivalent of I2 or ICl, respectively, gave the desired products upon crystallization at low temperature. The non‐stoichiometric octahalide [I3.6Cl4.4]2− was obtained after heating a CH2Cl2 solution of the ICl2− salt to reflux for 2 hours followed crystallization. [I4Cl4]2− is best described as two ICl2− anions bridged by I2, whereas [I3Cl5]2− is best described as an [I2Cl3]− pentahalide with a weak halogen bond to an ICl2− trihalide. The octahalides were characterized by X‐ray crystallography, computational studies, Raman and Far‐IR spectroscopies, as well as by TGA and melting point.