Two unique ZnI‐containing MOFs {[ZnI8ZnII3(H2O)x(HL)12](OH)2⋅13 H2O}n (x=6, 1; x=2, 2) (HL=tetrazole monoanion) with high‐nuclearity Zn‐cages were prepared successfully. These Zn‐cages are constructed from [ZnI8] clusters with multi‐centered ZnI−ZnI bonds and ZnII ions. [ZnI8] clusters in 1 and 2 display Oh and D4h symmetry, respectively. Importantly, eight [ZnI8] clusters and six ZnII ions form a large [Zn70] nanocage in 1. To our knowledge, this is the first MOF based on polynuclear Zn‐cages consisting of ZnI and ZnII ions. Compared with reported ZnI‐species, 1 and 2 display high thermal and solvent stabilities. Theoretical investigations based on DFT calculations uncover that effective 4s‐4s orbital overlap and electron delocalization through these a1g+t1u molecular orbitals on [ZnI8] clusters lead to considerable aromatic stabilization, which can explain well the intrinsic stability of 1 and 2. Interestingly, 1 can behave as a luminescent probe to detect the toxic CrVI ions in aqueous.