In this paper, the fabrication, characterization, and application in oxygen sensing are reported for a novel multifunctional nanomaterial of [Ru(bpy)(2)phen-MMS] (bpy, 2,2'-bipyridyl; phen, phenathrolin) which was simply prepared by covalently grafting the ruthenium(II) polypyridyl compounds into the channels of magnetic mesoporous silica nanocomposites (MMS). Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, N-2 adsorption-desorption, a superconducting quantum interference device, UV-vis spectroscopy, and photoluminescence spectra were used to characterize the samples. The well-designed multifunctional nanocomposites show superparamagnetic behavior and ordered mesoporous characteristics and exhibit a strong red-orange metal-to-ligand charge transfer emission. In addition, the obtained nanocomposites give high performance in oxygen sensing with high sensitivity (I-0/I-100 = 5.2), good Stern-Volmer characteristics (R-2 = 0.9995), and short response/recovery times (t down arrow = 6 s and t up arrow = 12 s). The magnetic, mesoporous, luminescent, and oxygen-sensing properties of this multifunctional nanostructure make it hold great promise as a novel multifunctional oxygen-sensing system for chemical/biosensor.