CsC5H2(NO2)3 crystallizes in the monoclinic C2/c space group. Cs(1) is bonded in a 9-coordinate geometry to one O(2), one O(4), one O(5), two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms. The Cs(1)-O(2) bond length is 3.17 Å. The Cs(1)-O(4) bond length is 3.27 Å. The Cs(1)-O(5) bond length is 3.29 Å. There is one shorter (3.21 Å) and one longer (3.31 Å) Cs(1)-O(1) bond length. There is one shorter (3.09 Å) and one longer (3.10 Å) Cs(1)-O(3) bond length. There is one shorter (3.09 Å) and one longer (3.21 Å) Cs(1)-O(6) bond length. There are five inequivalent C sites. In the first C site, C(3) is bonded in a distorted single-bond geometry to one C(2), one C(4), and one O(3) atom. The C(3)-C(2) bond length is 1.46 Å. The C(3)-C(4) bond length is 1.46 Å. The C(3)-O(3) bond length is 1.25 Å. In the second C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one C(5), and one N(2) atom. The C(4)-C(5) bond length is 1.37 Å. The C(4)-N(2) bond length is 1.45 Å. In the third C site, C(5) is bonded in a distorted trigonal planar geometry to one C(4), one N(3), and one H(2) atom. The C(5)-N(3) bond length is 1.37 Å. The C(5)-H(2) bond length is 1.09 Å. In the fourth C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(3), and one H(1) atom. The C(1)-C(2) bond length is 1.39 Å. The C(1)-N(3) bond length is 1.36 Å. The C(1)-H(1) bond length is 1.09 Å. In the fifth C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(3), and one N(1) atom. The C(2)-N(1) bond length is 1.44 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one C(2), one O(1), and one O(2) atom. The N(1)-O(1) bond length is 1.25 Å. The N(1)-O(2) bond length is 1.24 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one C(4), one O(4), and one O(5) atom. The N(2)-O(4) bond length is 1.24 Å. The N(2)-O(5) bond length is 1.25 Å. In the third N site, N(3) is bonded in a trigonal planar geometry to one C(1), one C(5), and one O(6) atom. The N(3)-O(6) bond length is 1.32 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(5) atom. There are six inequivalent O sites. In the first O site, O(3) is bonded in a single-bond geometry to two equivalent Cs(1) and one C(3) atom. In the second O site, O(4) is bonded in a single-bond geometry to one Cs(1) and one N(2) atom. In the third O site, O(5) is bonded in a single-bond geometry to one Cs(1) and one N(2) atom. In the fourth O site, O(6) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one N(3) atom. In the fifth O site, O(2) is bonded in a single-bond geometry to one Cs(1) and one N(1) atom. In the sixth O site, O(1) is bonded in a single-bond geometry to two equivalent Cs(1) and one N(1) atom. Linkers: 4 O=C1C([N+](=O)[O-])=C[N+]([O-])C=C1[N+](=O)[O-]. Metal clusters: 4 [Cs]. The MOF has largest included sphere 2.07 A, density 2.43 g/cm3, surface area 2951.90 m2/g, accessible volume 0.08 cm3/g