In the title compound, [Hg(NCS)(2)(C(11)H(6)N(2)O)], the Hg(II) atom, lying on a twofold rotation axis, is four-coordinated in a distorted tetra-hedral geometry by an N,N'-bidentate diaza-fluoren-9-one ligand and two thio-cyanate anions. In the crystal, inter-molecular C-H⋯N and C-H⋯O hydrogen bonds are effective in the stabilization of the structure.