The title compounds, bis[1,2-dicarba-closo-dodecaboran(12)-1-yl]mercury(II) dichloromethane solvate, [Hg(C(2)B(10)H(11))(2)].CH(2)Cl(2), (I), and bis[1,12-dicarba-closo-dodecaboran(12)-1-yl]mercury(II) tetrahydrofuran solvate, [Hg(C(2)B(10)H(11))(2)].C(4)H(8)O, (II), were prepared in excellent yields using a robust synthetic procedure involving the reaction of HgCl(2) with the appropriate monolithiocarborane. X-Ray analysis of the products revealed strong interactions between the Hg atoms in both complexes and the respective lattice solvent. The distances between the Hg(II) centers and the Cl atoms of the dichloromethane solvent molecule in the ortho-carborane derivative, (I), and the O atom of the tetrahydrofuran molecule in the para-carborane complex, (II), are shorter than the sums of the van der Waals radii for Hg and Cl (3.53 A), and Hg and O (3.13 A), respectively, indicating moderately strong interactions. There are two crystallographically independent molecules in the asymmetric unit of both compounds, which, in each case, are related by differing relative positions of the cages.