Reactions of 1,4-diazabicyclo[2.2.2]octane (“dabco”) with K2[HgI4] or Hg(SCN)2 yield crystals of [Hg(dabco)I2] (1) and [Hg(dabco)(SCN)2] (2). 1 crystallizes monoclinically, space group P21/a. Z = 4, a = 1211.6(5), b = 682.3(6), c = 1430.4(3) pm, β = 98.90(5)°; 2 is orthorhombic, space group Pmmn, Z = 2, a - 740.5(3), b = 609.1(4), c = 1220.0(8) pm. In 1 HgI2 groups are connected by bridging dabco molecules to give a chain structure. The Hg atoms are tetrahedrally coordinated. In 2 the Hg atoms are bridged by two SCN ligands and the chains thus formed are again interconnected by bridging dabco molecules, whereby layers are formed. The coordination polyhedron for the Hg atoms is a distorted octahedron.