Ni3C8(N3O4)2 crystallizes in the trigonal P3_121 space group. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a T-shaped geometry to one N(2), one N(3), and one O(1) atom. The Ni(1)-N(2) bond length is 2.05 Å. The Ni(1)-N(3) bond length is 2.07 Å. The Ni(1)-O(1) bond length is 2.15 Å. In the second Ni site, Ni(2) is bonded in an octahedral geometry to two equivalent N(1), two equivalent O(1), and two equivalent O(2) atoms. Both Ni(2)-N(1) bond lengths are 2.00 Å. Both Ni(2)-O(1) bond lengths are 2.09 Å. Both Ni(2)-O(2) bond lengths are 2.11 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 N(2) and one N(3) atom. The C(1)-N(2) bond length is 1.35 Å. The C(1)-N(3) bond length is 1.34 Å. In the second C site, C(2) is bonded in a 3-coordinate geometry to one C(4), one N(1), and one N(2) atom. The C(2)-C(4) bond length is 1.50 Å. The C(2)-N(1) bond length is 1.31 Å. The C(2)-N(2) bond length is 1.33 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(3) atom. The C(3)-O(1) bond length is 1.29 Å. The C(3)-O(3) bond length is 1.23 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(2), and one O(4) atom. The C(4)-O(2) bond length is 1.27 Å. The C(4)-O(4) bond length is 1.24 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one Ni(2), one C(2), and one N(3) atom. The N(1)-N(3) bond length is 1.36 Å. In the second N site, N(2) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one C(1), and one C(2) atom. In the third N site, N(3) is bonded in a 3-coordinate geometry to one Ni(1), one C(1), and one N(1) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Ni(1), one Ni(2), and one C(3) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Ni(2) and one C(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one C(3) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one C(4) atom. Linkers: 5 [O]C(=O)C1=NC(C([O])=O)=N[N]1 ,1 [O]C(=O)C1=NN=C(C([O])=O)[N]1. Metal clusters: 9 [Ni]. The MOF has largest included sphere 6.28 A, density 1.20 g/cm3, surface area 3093.92 m2/g, accessible volume 0.52 cm3/g