Multiplexing and biocompatible nanoparticle system have recently become an attractive research field. One of the rapidly developing research subjects is their biomedical applications, including magnetic resonance imaging (MRI) contrast agent, magnetic hyperthermia therapy, targeted drug delivery, biosensors and rapid biological separation. Because mesoporous silicas possess unique properties of high surface area, large pore volume, uniform pore size, and low cytotoxicity, multifunctional mesoporous composites that display both magnetic and luminescent functionalities would be very useful in biomedical applications.