Decoding the principles of cluster-based framework assembly at the molecular level remains a persistent challenge. Herein, we isolated and characterized a novel water-stable three-dimensional (3D) metal organic open framework [Cl@Ag-14(cPrC equivalent to C)(10)Cl-2 center dot(p-TOS)center dot 1/3H(2)O](n) (SD/Ag14, cPrC equivalent to CH = cyclopropylacetylene; p-TOS = p-toluenesulfonate), which contains a chloride-templated Ag-14 cluster as building block. For SD/Ag14, one chloride acts as the template to shape the Ag-14 cluster and the other bridges the clusters to a 3D pcu-h open framework. As revealed by high resolution electrospray mass spectrometry (HRESI-MS), the Ag-12-Ag-14 species are potential cluster-based intermediates to the 3D pcu-h framework, which authenticates a preconceived idea that the 3D framework is hierarchically assembled from the silver clusters as observed in solid state. Interestingly, SD/Ag14 can be used effectively to remove the environmental pollutant Cr2O72- from wastewater through anion exchange in a single-crystal-to-single-crystal (SC-SC) transformation fashion. Furthermore, SD/Ag14 exhibits excellent antibacterial activity against Staphylococcus aureus, thus making it a potential antibacterial agent.