The compound, MeHgSC 6 H 4 NO 2 -o, crystallizes in the monoclinic space group, P2 1 /n with Z = 8. In each of the two independent molecules of MeHgSC 6 H 4 NO 2 -o, there is a S---O intramolecular interaction [2.73(2) (molecule A) and 2.81 (2) 9 (molecule B)] with the three nearest intermolecular neighbours to each Hg atom being 2 S and 1 O atoms: in molecule A, Hg---O = 3.48(2), Hg---S = 3.322(4) and 3.539(4) 9; in molecule B, Hg---O = 3.61 (3), Hg---S = 3.257(4) and 3.647(5) 9. The geometry at Hg becomes trigonal bipyramidal if all three of these secondary contacts are included with the primary linear bonds [Hg--C = 2.08(2) and Hg--S = 2.379(4) 9, C--Hg--S = 176.4(5)° in molecule A; Hg--C = 2.04(2) and Hg--S = 2.366(4) 9, C--Hg--S = 177.0(5)° in molecule B]. The intramolecular (H 3 )C--Hg--S---O(NO) fragment is near linear in each of the two independent molecules.