Photothermal　therapy　(PTT)　possesses　a　great　promise　for　tumor　therapy　due　to　its　effective　tumor　inhibition　and　minimal　invasiveness.　Nevertheless,　most　of　organic　photothermal　agents　(PTAs)　suffer　from　poor　photothermal　conversion　efficiency,　and　the　residues　of　PTAs　may　cause　the　problem　of　side　effects.　Herein,　we　utilize　a　molecular　surgery　approach　to　develop　a　self-degradable　nanostructured　PTA　(NanoPcDA2).　NanoPcDA2　exhibited　a　remarkable　photothermal　conversion　efficiency.　In　addition,　NanoPcDA2　showed　an　outstanding　tumor　accumulation　after　intravenous　injection,　and　92%　tumor　growth　was　suppressed　in　the　mice　tumor　model　at　a　low　light　dose　of　300　J　cm(-2)　and　a　NanoPcDA2　dose　of　0.8　nmol　g(-1).　Moreover,　NanoPcDA2　can　be　degraded　by　singlet　oxygen　(O-1(2))　produced　by　itself　and　lose　its　photoactivity　after　PTT.　Notably,　the　photodegradation　products　of　NanoPcDA2　have　negligible　cytotoxicity.　In　this　way,　it　not　only　contributes　to　resolve　the　potential　phototoxicity　problems　of　residual　PTAs,　but　also　can　expedite　the　metabolism　of　PTAs　to　avert　the　potential　biotoxicity　of　drug　accumulation.