Cuprous Halide Coordination Polymers Based on Cationic [Cu 4 X 2 ] and [Cu 3 X] Clusters and [Cu 2 Br] n Layers with Tetrazolates as Assembling Ligands: Highly Connected Networks and Halide‐Dependent Luminescence

Five tetrazolate‐based coordination polymers with cationic copper(I) halide motifs, namely, Cu 4 (tta) 2 Cl 2 ( 1 , tta = tetrazolate), Cu 4 (tta) 2 Br 2 ( 2 ), Cu 2 (tta)I ( 3 ), Cu 3 (mtta) 2 Cl ( 4 , mtta = 5‐methyltetrazolate), and Cu 2 (tta)Br ( 5 ) were prepared by hydro(solvo)thermal reactions of CuX 2 or CuX with tetrazolato ligands in the presence of HX. Compounds 1 , 2 , and 3 show eight‐connected square‐planar layered structures constructed with butterfly‐like [Cu 4 X 2 ] 2+ (X = Cl, Br, I) clusters and μ 4 ‐tta groups. Isomorphs 1 and 2 crystallize in the orthorhombic space group Pbca , but 3 crystallizes in the orthorhombic space group Pbam , because each μ 4 ‐tta group is coordinated to three butterfly‐like clusters rather than four in 1 and 2 . To the best of our knowledge, 1 , 2 , and 3 represent the only 2D coordination polymers with eight‐connected square planar topology to date. Compound 4 is a [Cu 3 Cl] 2+ cluster based on the undocumented ten‐connected ZrIn 2 topological framework. Compound 5 has a 3D pillar layered framework constructed with [Cu 2 Br] n n + cationic layers. Compounds 1 , 2 , 4 , and 5 exhibit strong green‐blue emission in the solid state at room temperature, whereas cuprous iodide complex 3 shows strong red luminescence.