CuC4H2(NO)2 crystallizes in the tetragonal I4_1/a space group. Cu(1) is bonded in a rectangular see-saw-like geometry to one N(1), one N(2), one O(1), and one O(2) atom. The Cu(1)-N(1) bond length is 1.97 Å. The Cu(1)-N(2) bond length is 1.96 Å. The Cu(1)-O(1) bond length is 1.95 Å. The Cu(1)-O(2) bond length is 2.02 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(1), and one O(2) atom. The C(1)-C(4) bond length is 1.48 Å. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.25 Å. In the second C site, C(2) is bonded in a distorted single-bond geometry to one C(3), one C(4), and one H(2) atom. The C(2)-C(3) bond length is 1.38 Å. The C(2)-C(4) bond length is 1.40 Å. The C(2)-H(2) bond length is 0.93 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(2), one N(1), and one H(1) atom. The C(3)-N(1) bond length is 1.36 Å. The C(3)-H(1) bond length is 0.93 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(1), one C(2), and one N(2) atom. The C(4)-N(2) bond length is 1.36 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Cu(1), one C(3), and one N(2) atom. The N(1)-N(2) bond length is 1.35 Å. In the second N site, N(2) is bonded in a 3-coordinate geometry to one Cu(1), one C(4), and one N(1) atom. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(2) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cu(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one C(1) atom. Linkers: 2 [O]C(=O)C1=C[CH]N=N1 ,1 [O]C(=O)C1=CC=N[N]1 ,3 [O]C(=O)C1=NN=C[CH]1 ,1 [O]C(=O)[C]1C=CN=N1 ,1 [O]C(=O)C1=N[N]C=C1. Metal clusters: 8 [Cu]. The MOF has largest included sphere 9.67 A, density 0.77 g/cm3, surface area 3403.31 m2/g, accessible volume 0.97 cm3/g