CuC2N5H4 crystallizes in the tetragonal P4_2/n space group. Cu(1) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(4) atom. The Cu(1)-N(1) bond length is 1.94 Å. The Cu(1)-N(2) bond length is 1.95 Å. The Cu(1)-N(4) bond length is 1.96 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(2), one N(3), and one N(4) atom. The C(1)-N(2) bond length is 1.33 Å. The C(1)-N(3) bond length is 1.38 Å. The C(1)-N(4) bond length is 1.36 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(1), one N(4), and one N(5) atom. The C(2)-N(1) bond length is 1.34 Å. The C(2)-N(4) bond length is 1.37 Å. The C(2)-N(5) bond length is 1.37 Å. There are five inequivalent N sites. In the first N site, N(2) is bonded in a 3-coordinate geometry to one Cu(1), one C(1), and one N(1) atom. The N(2)-N(1) bond length is 1.41 Å. In the second N site, N(3) is bonded in a distorted trigonal non-coplanar geometry to one C(1), one H(1), and one H(2) atom. The N(3)-H(1) bond length is 1.02 Å. The N(3)-H(2) bond length is 1.02 Å. In the third N site, N(4) is bonded in a trigonal planar geometry to one Cu(1), one C(1), and one C(2) atom. In the fourth N site, N(1) is bonded in a 3-coordinate geometry to one Cu(1), one C(2), and one N(2) atom. In the fifth N site, N(5) is bonded in a trigonal non-coplanar geometry to one C(2), one H(3), and one H(4) atom. The N(5)-H(3) bond length is 1.03 Å. The N(5)-H(4) bond length is 1.03 Å. There are four inequivalent H sites. In the first H site, H(4) is bonded in a single-bond geometry to one N(5) atom. In the second H site, H(1) is bonded in a single-bond geometry to one N(3) atom. In the third H site, H(2) is bonded in a single-bond geometry to one N(3) atom. In the fourth H site, H(3) is bonded in a single-bond geometry to one N(5) atom. Linkers: 5 NC1=[N]=C(N=N1)N. Metal clusters: 1 N1=N[Cu]=NN=[Cu]1 ,6 [Cu]. The MOF has largest included sphere 1.81 A, density 2.51 g/cm3, surface area 3028.73 m2/g, accessible volume 0.06 cm3/g