A pillared-layer strategy is employed to assist the construction of two water-stable Zn-based metal-organic frameworks (MOFs) in this work, [ZnL(Bipy)]·0.5H2O (1) and [ZnL(Bpyb)]·1.5H2O (2) (H2L = 5-(pyridine-4-yl)isophthalic acid, Bipy = 4,4'-bipyridine, and Bpyb = 1,4-bis(pyrid-4-yl)benzene). The linkage of Zn centers and L2- ligands affords the layer structures, which are further pillared by the linear N-donor ligands to the three-dimensional architectures. The "pillars" with diverse molecular lengths lead to different pore sizes in 1 and 2, which show different sorption behaviors for iodine capture. Additionally, the photoluminescence properties of compounds 1 and 2 were investigated. Moreover, the photoluminescence sensing experiment indicates that compound 1 can be considered to be a promising selective sensor for Fe3+.