​Periodic mesoporous organosilica nanoparticles emerge as promising vectors for nanomedicine applications.  Their properties are very different from those of well-known mesoporous silica nanoparticles as there is no silica source for their synthesis.  So far, they have only been synthesized from small bis-silylated org. precursors.  However, no studies employing large stimuli-responsive precursors have been reported on such hybrid systems yet.  Here, the synthesis of porphyrin-based organosilica nanoparticles from a large octasilylated metalated porphyrin precursor is described for applications in near-IR two-photon-triggered spatiotemporal theranostics.  The nanoparticles display unique interconnected large cavities of 10-80 nm.  The framework of the nanoparticles is constituted with J-aggregates of porphyrins, which endows them with two-photon sensitivity.