The first example of one single crystal containing two different organic-inorganic hybrid openframework structures was obtained using ah ydro(solvo)thermal methoda nd structurally characterized by singlecrystal X-ray diffraction. Remarkably,u nder the same synthetic conditions, the zinc ions are respectively coordinated by oxalic acid( OX) and 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (TIMB) linkerst of orm two significantly different frameworks:a nionic [Zn 2 (OX) 3 ] 2À and cationic [Zn(TIMB)] 2 + networks that interweavew ith each other to give an unprecedented interpenetrating structure with two differently-bonded open-frameworks. From the inorganic chemistry perspective, it is extremelyd ifficult to control to which metal center the oxygen-donor linkers or/and nitrogen-donor ligands bind. Am ixed Co/Zn analogue wasa lso obtained by as imilar method. The singlecrystal XRD and EDS analyses indicatet hat the octahedral Zn ions of the anionic framework are replaced by cobalt cations, whereas the Zn ions in the tetrahedral positions of the cationic networks remain intact. This leads to the formation of the interpenetrating analogue with am ixed metal composition. Furthermore, NTOU-5 shows structural stability and efficientlyr emoves organic dyes from aqueous solutions at concentrations of 10 ppm.Crystale ngineering is one of the most important research topics because the development of new crystalline compounds leads to interesting applications. Moreover,i nvestigating the rich structuralc hemistry and structure-property relationships make this av ery attractive research field. [1][2][3] Great efforts have also been devoted to the design and synthesiso fn ew coordination polymers and metal-organic frameworks by matching metal nodes and flexible spacerl inkers, because of the inter-esting structuralf eatures and their applicationsi ng as storage, catalysis, molecular sensing, and adsorption. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] For the bottom-up synthesis of those hybrid materials with new components and architectures,s tructure prediction remainso ne of the most difficult challenges. [18][19][20] There are many factors, such as reaction temperature, the ratio of reactants, pH, etc.,that influence the structural buildingu nits and block packing modes, which eventually lead to one-dimensional (1D) chains, 2D networks, 3D frameworks, and interpenetrated structures.C omplicated interpenetrating architectures have stimulated the collaboration between the fields of crystal growth, design,a nd engineering for the fabrication of new topological and/or functional materials. So far,n umerousc ompounds with av ariety of interlocked structures were reported. [18][19][20][21][22][23][24][25] However,c rystalline structures in which the networks consist of different topologies and/or dimensions that interpenetrate are still very rare. Two compounds displayed interesting structural features:one cagewithin-cage porous solid built from two zeolite-type frameworks possessed an interpenetrating structure with Zn 2...

An interpenetrating structure (NTOU‐5) is reported, built from two differently bonded open frameworks by a hydro‐(solvo)thermal method and its structural features were characterized by single‐crystal XRD. A mixed metal analogue can also be obtained through a similar method. Moreover, the title compound shows its structural stability and efficient captures of organic dye pollutants from aqueous solutions even at concentrations as low as 10 ppm, which is similar to the pollutant content in industrial wastewater. More information can be found in the Communication by C.‐M. Wang et al. on page 7815.