Self-assembled polymeric nanocapsules.(NCs) that incorporate dendrimer porphyrin (DP) in the shells and superpararnagnetic iron oxide nanoparticles (SPIONs) in the cores are fabricated to create a theragnostic platform for the application in photodynamic therapy (PDT) and magnetic resonance imaging (MRI). SPIONs-embedded polystyrene NPs (SPIONs@PS) are used as a template to build up multilayered NCs. The formation of PAH/DP multilayer on the SPIONs@PS is monitored by zeta-pential and fluorescence emission measurement, because the porphyrin unit in the core of DP has strong red fluorescence emission. NCs have strong enough magnetic property (>20 emu/g) for MRI application with typical superparamagnetic behavior, where the linear correlation of R2 and Fe concentration at diluted conditions led to corresponding T2 relaxivity coefficient (r2) value of 93.5 mM(-1) s(-1). Cell viability study upon light irradiation reveals that NCs can successfully work in photosensitizer formulation for PDT.