Metal-organic frameworks (MOFs) and MOF-based composites as luminescent sensors with excellent economic practicability and handy operability have attracted much attention. Herein, we designed and fabricated a porous Zn-based MOF, [Zn(OBA)(L)·2DMA] [; HOBA = 4,4'-oxybis(benzoic acid), L = 2,4,6-tris(4-pyridyl)pyridine, and DMA = ,-dimethylacetamide], with mixed nodes under solvothermal conditions, and the pore size of 5.9 Å was calculated from N adsorption isotherms by using a density functional theory model. The as-synthesized compound is stable in different boiling organic solvents and water solutions with a wide pH range of 2-12 and exhibits intense luminescence emission at 360 nm under excitation of 290 nm. Significantly, compound shows high selective detection of Fe, CrO, and CrO in aqueous solution even under the interference of other ions. Compound can quickly sense these ions in a short time and has a striking sensitivity toward Fe with an ultralow limit of detection (LOD) of 1.06 μM. The relatively low LODs for CrO and CrO are 3.87 and 2.37 μM, respectively, compared to the reported works. Meanwhile, compound can be reused to detect Fe, CrO, and CrO six times by simple regeneration. Considering the practicability, a mixed-matrix membrane (MMM) incorporated compound and poly(methyl methacrylate) has been constructed. This MMM displays quick detection of Fe, CrO, and CrO and prompt regeneration by lifting from the analyte. This useful MMM shows a comparable LOD below 4.35 μM for these ions. This work presents a cost-effective Zn-based MOF as a functional platform for simple but useful sensing of Fe, CrO, and CrO in aqueous solution.