The title compound, [Fe(C10H15)2][Ni(C3OS4)2]·C4H8O or [Fe(Cp*)2][Ni(dmio)2]·THF, where [Fe(Cp*)2]+ is the decamethylferrocenium cation, dmio is the 2-oxo-1,3-dithiole-4,5-dithiolate dianion and THF is tetrahydrofuran, crystallizes with two independent half-anion units [one Ni atom is at the centre of symmetry ( , , 0) and the other is at the centre of symmetry ( , 0, )], one cation unit (located in a general position) and one THF solvent molecule in the asymmetric unit. The crystal structure consists of two-dimensional layers composed of parallel mixed chains, where pairs of cations alternate with single anions. These layers are separated by sheets of anions and THF molecules. [ABSTRACT FROM AUTHOR]