ErC12H12(NO)6(C5H2)6 is Indium-derived structured and crystallizes in the trigonal R-3c space group. The structure is zero-dimensional and consists of eighteen C5H2 clusters and six ErC12H12(NO)6 clusters. In each C5H2 cluster, there are five inequivalent C sites. In the first C site, C(2) is bonded in a distorted single-bond geometry to one C(3) and one H(2) atom. The C(2)-C(3) bond length is 1.42 Å. The C(2)-H(2) bond length is 0.93 Å. In the second C site, C(3) is bonded in a 4-coordinate geometry to one C(2), one C(4), one C(6), and one C(7) atom. The C(3)-C(4) bond length is 1.39 Å. The C(3)-C(6) bond length is 1.52 Å. The C(3)-C(7) bond length is 1.52 Å. In the third C site, C(4) is bonded in a distorted single-bond geometry to one C(3) and one H(3) atom. The C(4)-H(3) bond length is 0.93 Å. In the fourth C site, C(6) is bonded in a 3-coordinate geometry to one C(3) and two equivalent C(7) atoms. There is one shorter (0.83 Å) and one longer (1.25 Å) C(6)-C(7) bond length. In the fifth C site, C(7) is bonded in a distorted T-shaped geometry to one C(3) and two equivalent C(6) atoms. There are two inequivalent H sites. In the first H site, H(2) is bonded in a single-bond geometry to one C(2) atom. In the second H site, H(3) is bonded in a single-bond geometry to one C(4) atom. In each ErC12H12(NO)6 cluster, Er(1) is bonded in an octahedral geometry to six equivalent O(1) atoms. All Er(1)-O(1) bond lengths are 2.23 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(1) atom. The C(1)-N(1) bond length is 1.35 Å. The C(1)-H(1) bond length is 0.93 Å. In the second C site, C(5) is bonded in a distorted bent 120 degrees geometry to one N(1) and one H(4) atom. The C(5)-N(1) bond length is 1.35 Å. The C(5)-H(4) bond length is 0.93 Å. N(1) is bonded in a trigonal planar geometry to one C(1), one C(5), and one O(1) atom. The N(1)-O(1) bond length is 1.33 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(4) is bonded in a single-bond geometry to one C(5) atom. O(1) is bonded in a bent 120 degrees geometry to one Er(1) and one N(1) atom. Linkers: 18 [O-][N+]1C=CC2(C=C1)[C]1[C][C][C]12.[O-][n+]1cc[c]cc1. Metal clusters: 6 [O][Er]([O])([O])([O])([O])[O]. RCSR code: pcu. The MOF has largest included sphere 4.57 A, density 1.36 g/cm3, surface area 3976.72 m2/g, accessible volume 0.24 cm3/g