NiH8(C3N)4 crystallizes in the monoclinic C2/c space group. Ni(1) is bonded in a square co-planar geometry to two equivalent N(1) and two equivalent N(2) atoms. Both Ni(1)-N(1) bond lengths are 1.87 Å. Both Ni(1)-N(2) bond lengths are 1.86 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(3), one N(1), and one H(3) atom. The C(1)-C(3) bond length is 1.41 Å. The C(1)-N(1) bond length is 1.35 Å. The C(1)-H(3) bond length is 1.08 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(3), one N(2), and one H(4) atom. The C(2)-C(3) bond length is 1.41 Å. The C(2)-N(2) bond length is 1.35 Å. The C(2)-H(4) bond length is 1.08 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(1), one C(2), and one C(4) atom. The C(3)-C(4) bond length is 1.46 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(3), one C(5), and one C(6) atom. The C(4)-C(5) bond length is 1.41 Å. The C(4)-C(6) bond length is 1.41 Å. In the fifth C site, C(5) is bonded in a distorted trigonal planar geometry to one C(4); one C(6); and one H(1,2) atom. The C(5)-C(6) bond length is 1.39 Å. The C(5)-H(1,2) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(4); one C(5); and one H(1,2) atom. The C(6)-H(1,2) bond length is 1.09 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Ni(1), one C(1), and one N(2) atom. The N(1)-N(2) bond length is 1.36 Å. In the second N site, N(2) is bonded in a distorted trigonal planar geometry to one Ni(1), one C(2), and one N(1) atom. There are three inequivalent H sites. In the first H site, H(1,2) is bonded in a single-bond geometry to one C(5) atom. In the second H site, H(3) is bonded in a single-bond geometry to one C(1) atom. In the third H site, H(4) is bonded in a single-bond geometry to one C(2) atom. Linkers: 2 C1=N[N]C=C1c1ccc([C]2C=NN=C2)cc1. Metal clusters: 2 [Ni]. The MOF has largest included sphere 8.38 A, density 0.87 g/cm3, surface area 4306.31 m2/g, accessible volume 0.71 cm3/g