A rare isomer of the {Mo8O28}8− anion has been trapped from an acidified aqueous solution of molybdate by using the {Mo2O2S2}2+ oxothio cation as the linker and isolated as a part of a unique macrocyclic anion, which consists of four isopolyoxomolybdate fragments {Mo8O28} bridged by four {Mo2O2S2} units.