Tetramesityldibismuthane is obtained by the reaction of Mes2BiCl (Mes = 2,4,6-(CH3)3C6H2) and LiEH4 (E = B, Al) with intermediate formation of Mes2BiH. Crystals of Mes4Bi2 consist of centrosymmetric tetramesityldibismuthane molecules in the trans conformation. The value of the Bi-Bi bond length is 3.087(3) Å .