ZnC3N3H2O2 crystallizes in the monoclinic P2_1/c space group. Zn(1) is bonded in a trigonal bipyramidal geometry to one N(1), one N(2), one N(3), one O(1), and one O(2) atom. The Zn(1)-N(1) bond length is 2.03 Å. The Zn(1)-N(2) bond length is 2.02 Å. The Zn(1)-N(3) bond length is 2.11 Å. The Zn(1)-O(1) bond length is 2.24 Å. The Zn(1)-O(2) bond length is 2.03 Å. There are three inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(2) atom. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.27 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(1), one N(2), and one H(1) atom. The C(2)-N(1) bond length is 1.35 Å. The C(2)-N(2) bond length is 1.33 Å. The C(2)-H(1) bond length is 1.08 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(2) atom. The C(3)-N(1) bond length is 1.35 Å. The C(3)-N(3) bond length is 1.33 Å. The C(3)-H(2) bond length is 1.08 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded in a 3-coordinate geometry to one Zn(1), one C(3), and one N(2) atom. The N(3)-N(2) bond length is 1.37 Å. In the second N site, N(1) is bonded in a trigonal planar geometry to one Zn(1), one C(2), and one C(3) atom. In the third N site, N(2) is bonded in a distorted trigonal planar geometry to one Zn(1), one C(2), and one N(3) atom. There are two 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. There are two inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to one Zn(1) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Zn(1) and one C(1) atom. Linkers: 1 C1=NN=C[N]1 ,3 C1=NC=N[N]1 ,1 [O]C(=O)C([O])=O. Metal clusters: 4 [Zn]. The MOF has largest included sphere 4.28 A, density 1.57 g/cm3, surface area 3341.04 m2/g, accessible volume 0.27 cm3/g