Multimodal　imaging　in　the　second　near-infrared　window　(NIR-II)　guided　cancer　therapy　is　a　highly　precise　and　efficient　cancer　theranostic　strategy.　However,　it　is　still　a　challenge　to　develop　activated　NIR-II　optical　imaging　and　therapy　agents.　In　this　study,　we　develop　a　pH-responsive　hybrid　plasmonic-fluorescent　vesicle　by　self-assembly　of　amphiphilic　plasmonic　nanogapped　gold　nanorod　(AuNNR)　and　fluorescent　down-conversion　nanoparticles　(DCNP)　(AuNNR-DCNP　Ve),　showing　remarkable　and　activated　NIR-II　fluorescence　(FL)/NIR-II　photoacoustic　(PA)　imaging　performances.　The　hybrid　vesicle　also　exhibited　superior　loading　capacity　of　doxorubicin　as　a　superior　drug　carrier　and　efficient　radiosensitizer　for　X-ray-induced　radiotherapy.　Interestingly,　the　accumulated　hybrid　AuNNR-DCNP　Ve　in　the　tumor　resulted　in　a　recovery　of　NIR-II　FL　imaging　signal　and　a　variation　in　NIR-II　PA　imaging　signal.　Dual　activated　NIR-II　PA　and　FL　imaging　of　the　hybrid　vesicle　could　trace　drug　release　and　precisely　guided　cancer　radiotherapy　to　ultimately　reduce　the　side　effects　to　healthy　tissue.[Figure　not　available:　see　fulltext.].　©　2020,　Tsinghua　University　Press　and　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.