KBC4H4(N2O)4 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 11-coordinate geometry to one N(2), one N(3), one N(6), one N(7), one H(3), one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms. The K(1)-N(2) bond length is 2.90 Å. The K(1)-N(3) bond length is 2.87 Å. The K(1)-N(6) bond length is 3.02 Å. The K(1)-N(7) bond length is 2.92 Å. The K(1)-H(3) bond length is 2.92 Å. The K(1)-O(3) bond length is 3.29 Å. The K(1)-O(4) bond length is 3.39 Å. There is one shorter (2.85 Å) and one longer (3.02 Å) K(1)-O(1) bond length. There is one shorter (2.98 Å) and one longer (3.01 Å) K(1)-O(2) bond length. B(1) is bonded in a tetrahedral geometry to one N(1), one N(5), one H(1), and one H(3) atom. The B(1)-N(1) bond length is 1.56 Å. The B(1)-N(5) bond length is 1.56 Å. The B(1)-H(1) bond length is 1.21 Å. The B(1)-H(3) bond length is 1.21 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one N(1), one N(3), and one H(2) atom. The C(1)-N(1) bond length is 1.36 Å. The C(1)-N(3) bond length is 1.33 Å. The C(1)-H(2) bond length is 1.09 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one N(2), one N(3), and one N(4) atom. The C(2)-N(2) bond length is 1.33 Å. The C(2)-N(3) bond length is 1.35 Å. The C(2)-N(4) bond length is 1.44 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one N(5), one N(7), and one H(4) atom. The C(3)-N(5) bond length is 1.36 Å. The C(3)-N(7) bond length is 1.33 Å. The C(3)-H(4) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one N(6), one N(7), and one N(8) atom. The C(4)-N(6) bond length is 1.33 Å. The C(4)-N(7) bond length is 1.35 Å. The C(4)-N(8) bond length is 1.44 Å. There are eight inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one B(1), one C(1), and one N(2) atom. The N(1)-N(2) bond length is 1.35 Å. In the second N site, N(2) is bonded in a distorted single-bond geometry to one K(1), one C(2), and one N(1) atom. In the third N site, N(3) is bonded in a distorted water-like geometry to one K(1), one C(1), and one C(2) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one C(2), one O(1), and one O(2) atom. The N(4)-O(1) bond length is 1.25 Å. The N(4)-O(2) bond length is 1.24 Å. In the fifth N site, N(5) is bonded in a distorted trigonal planar geometry to one B(1), one C(3), and one N(6) atom. The N(5)-N(6) bond length is 1.35 Å. In the sixth N site, N(6) is bonded in a distorted single-bond geometry to one K(1), one C(4), and one N(5) atom. In the seventh N site, N(7) is bonded in a distorted water-like geometry to one K(1), one C(3), and one C(4) atom. In the eighth N site, N(8) is bonded in a trigonal planar geometry to one C(4), one O(3), and one O(4) atom. The N(8)-O(3) bond length is 1.24 Å. The N(8)-O(4) bond length is 1.24 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one B(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(1) atom. In the third H site, H(3) is bonded in a single-bond geometry to one K(1) and one B(1) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1) and one N(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1) and one N(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one K(1) and one N(8) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one K(1) and one N(8) atom. Linkers: 2 O=N(=O)c1ncn(n1)[BH2]n1cnc(n1)N(=O)=O ,2 O=N(=O)C1=N[CH]N([N]1)[BH2]n1cnc(n1)N(=O)=O. Metal clusters: 4 [K]. The MOF has largest included sphere 2.15 A, density 1.72 g/cm3, surface area 3000.34 m2/g, accessible volume 0.06 cm3/g