HgI2CuHgC10H6I2(NO)4 crystallizes in the orthorhombic Pnma space group. The structure consists of four mercury diiodide molecules inside a CuHgC10H6I2(NO)4 framework. In the CuHgC10H6I2(NO)4 framework, Cu(1) is bonded in an octahedral geometry to two equivalent N(1), two equivalent N(2), and two equivalent O(1) atoms. Both Cu(1)-N(1) bond lengths are 1.97 Å. Both Cu(1)-N(2) bond lengths are 2.50 Å. Both Cu(1)-O(1) bond lengths are 1.99 Å. Hg(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(2), one I(1), and one I(2) atom. Both Hg(1)-O(2) bond lengths are 2.60 Å. The Hg(1)-I(1) bond length is 2.68 Å. The Hg(1)-I(2) bond length is 2.66 Å. There are five inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one C(5), and one N(1) atom. The C(1)-C(2) bond length is 1.39 Å. The C(1)-C(5) bond length is 1.50 Å. The C(1)-N(1) bond length is 1.35 Å. In the second C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(2) atom. The C(5)-O(1) bond length is 1.30 Å. The C(5)-O(2) bond length is 1.25 Å. In the third C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one N(2), and one H(1) atom. The C(2)-N(2) bond length is 1.34 Å. The C(2)-H(1) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one N(1), and one H(3) atom. The C(4)-C(3) bond length is 1.40 Å. The C(4)-N(1) bond length is 1.34 Å. The C(4)-H(3) bond length is 1.09 Å. In the fifth C site, C(3) is bonded in a distorted trigonal planar geometry to one C(4), one N(2), and one H(2) atom. The C(3)-N(2) bond length is 1.34 Å. The C(3)-H(2) bond length is 1.09 Å. There are two inequivalent N sites. In the first N site, N(2) is bonded in a trigonal planar geometry to one Cu(1), one C(2), and one C(3) atom. In the second N site, N(1) is bonded in a trigonal planar geometry to one Cu(1), one C(1), and one C(4) atom. There are three inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(3) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(4) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Cu(1) and one C(5) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Hg(1) and one C(5) atom. There are two inequivalent I sites. In the first I site, I(1) is bonded in a single-bond geometry to one Hg(1) atom. In the second I site, I(2) is bonded in a single-bond geometry to one Hg(1) atom. Linkers: 8 [O]C(=O)c1cnccn1. Metal clusters: 4 [Cu] ,4 [Hg]. The MOF has largest included sphere 2.04 A, density 3.86 g/cm3, surface area 2093.40 m2/g, accessible volume 0.04 cm3/g