Cocrystallization of pyrene with Hg(CN)(2) gives a new clathrate, namely bis[dicyanidomercury(II)] pyrene solvate, [Hg(CN)(2)](2) x C(16)H(10), with molecules of pyrene embedded in cavities of the slightly deformed structure of the mercuric salt; the weak intermolecular N...Hg interactions present in pure Hg(CN)(2) are maintained in the cocrystal. The X-ray analysis of the resulting compound reveals unusual organic-inorganic interactions. One molecule of Hg(CN)(2) lies on a crystallographic mirror plane, while in the other, only the Hg atom is on the mirror plane. The molecule of pyrene is cut by a mirror plane perpendicular to the plane of the molecule.