Cu2C4N6H5O crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to one N(2), one N(3), one N(5), and one N(6) atom. The Cu(1)-N(2) bond length is 1.99 Å. The Cu(1)-N(3) bond length is 2.00 Å. The Cu(1)-N(5) bond length is 1.99 Å. The Cu(1)-N(6) bond length is 1.99 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent N(4) and two equivalent O(1) atoms. Both Cu(2)-N(4) bond lengths are 1.94 Å. Both Cu(2)-O(1) bond lengths are 2.04 Å. In the third Cu site, Cu(3) is bonded in a linear geometry to two equivalent N(1) atoms. Both Cu(3)-N(1) bond lengths are 1.96 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(4), one N(6), and one H(3) atom. The C(1)-N(4) bond length is 1.34 Å. The C(1)-N(6) bond length is 1.32 Å. The C(1)-H(3) bond length is 0.87 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(4), one N(5), and one H(1) atom. The C(2)-N(4) bond length is 1.36 Å. The C(2)-N(5) bond length is 1.32 Å. The C(2)-H(1) bond length is 0.98 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one N(1), one N(3), and one H(4) atom. The C(3)-N(1) bond length is 1.36 Å. The C(3)-N(3) bond length is 1.33 Å. The C(3)-H(4) bond length is 1.02 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one N(1), one N(2), and one H(5) atom. The C(4)-N(1) bond length is 1.35 Å. The C(4)-N(2) bond length is 1.32 Å. The C(4)-H(5) bond length is 0.84 Å. There are six inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Cu(3), one C(3), and one C(4) atom. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Cu(1), one C(4), and one N(3) atom. The N(2)-N(3) bond length is 1.38 Å. In the third N site, N(3) is bonded in a distorted trigonal planar geometry to one Cu(1), one C(3), and one N(2) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one Cu(2), one C(1), and one C(2) atom. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one C(2), and one N(6) atom. The N(5)-N(6) bond length is 1.38 Å. In the sixth N site, N(6) is bonded in a 3-coordinate geometry to one Cu(1), one C(1), and one N(5) atom. There are five 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 O(1) atom. The H(2)-O(1) bond length is 0.91 Å. In the third H site, H(3) is bonded in a single-bond geometry to one C(1) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(3) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(4) atom. O(1) is bonded in a bent 120 degrees geometry to one Cu(2) and one H(2) atom. Linkers: 2 O[Cu](O)(n1cnnc1)n1cnnc1 ,1 [N]1=CN=NC=1 ,1 C1=NN=C[N]1 ,2 C1=NC=N[N]1. Metal clusters: 6 [Cu]. The MOF has largest included sphere 6.88 A, density 1.01 g/cm3, surface area 3288.92 m2/g, accessible volume 0.62 cm3/g