KBC4N3HO2 crystallizes in the monoclinic Cc space group. K(1) is bonded in a 7-coordinate geometry to one N(3), two equivalent N(1), two equivalent N(2), one O(1), and one O(2) atom. The K(1)-N(3) bond length is 3.16 Å. There is one shorter (2.84 Å) and one longer (2.87 Å) K(1)-N(1) bond length. There is one shorter (2.89 Å) and one longer (2.94 Å) K(1)-N(2) bond length. The K(1)-O(1) bond length is 2.83 Å. The K(1)-O(2) bond length is 2.77 Å. B(1) is bonded in a tetrahedral geometry to one C(1), one C(2), one C(3), and one C(4) atom. The B(1)-C(1) bond length is 1.58 Å. The B(1)-C(2) bond length is 1.58 Å. The B(1)-C(3) bond length is 1.58 Å. The B(1)-C(4) bond length is 1.65 Å. There are four inequivalent C sites. In the first C site, C(1) is bonded in a linear geometry to one B(1) and one N(1) atom. The C(1)-N(1) bond length is 1.17 Å. In the second C site, C(2) is bonded in a linear geometry to one B(1) and one N(2) atom. The C(2)-N(2) bond length is 1.17 Å. In the third C site, C(3) is bonded in a linear geometry to one B(1) and one N(3) atom. The C(3)-N(3) bond length is 1.16 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one B(1), one O(1), and one O(2) atom. The C(4)-O(1) bond length is 1.35 Å. The C(4)-O(2) bond length is 1.23 Å. There are three inequivalent N sites. In the first N site, N(3) is bonded in a 3-coordinate geometry to one K(1), one C(3), and one H(1) atom. The N(3)-H(1) bond length is 1.72 Å. In the second N site, N(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and one C(1) atom. In the third N site, N(2) is bonded in a distorted single-bond geometry to two equivalent K(1) and one C(2) atom. H(1) is bonded in a single-bond geometry to one N(3) and one O(1) atom. The H(1)-O(1) bond length is 1.01 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one K(1), one C(4), and one H(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1) and one C(4) atom. Linkers: 2 N#C[B](C(=O)O)(C#N)C#N. Metal clusters: 2 [K]. The MOF has largest included sphere 1.71 A, density 1.60 g/cm3, surface area 2808.78 m2/g, accessible volume 0.07 cm3/g