In this work, a class of dual-functional nanoparticles (NPs) were facilely prepared from ZnPc and Fe3O4 NPs for photodynamic therapy (PDT) and magnetic resonance imaging (MRI). The as-synthesized NPs were investigated in terms of size, morphology, zeta potential, biocompatibility, optical and magnetic properties respectively. The aggregation degree of ZnPc in hybrid NPs was found to be considerably meliorated with the presence of Fe3O4 NPs, corresponding to higher O-1(2) generation rate. Based on the dual-functional NPs, MRI and in vitro PDT was carried out, respectively, yielding a high r2 relaxivity value of 152.9 mM(-1) s(-1) and strong photocytotoxicity. Given the facility of synthesis, such a strategy can be applied to prepare other multifunctional NPs by introducing other small-sized NPs, such as Au NPs (photothermal), quantum dots (fluorescence imaging), etc.