Aggregation-caused　quenching　(ACQ)　effects　of　photosensitizers　severely　cut　down　the　generation　of　quantum　yield　of　singlet　oxygen　(1O2)　for　effective　photodynamic　therapy　(PDT).　Herein,　we　accomplish　a　deaggregation-enhanced　1O2　production　strategy　by　the　noncovalent　coordination　of　a　clinically　applied　triterpenoid　oleanolic　acid　(OA)　and　hematoporphyrin　(Hp)　via　one-step　self-assembly,　forming　a　nanosensitizer　OH,　in　which　Hp　is　interspersed　on　the　surface　of　the　OA　matrix　in　a　face-to-face　manner.　The　scattered　arrangement　of　Hp　held　by　the　OA　matrix　decreases　the　π-π　aggregation　in　Hp,　leading　to　a　3.7-fold　boost　in　the　intracellular　1O2　yield　and　high　phototoxicity　in　vitro　and　in　vivo.　Moreover,　the　biologically　active　OA　enables　OH　to　display　excellent　cellular　uptake　efficiency　(increase　by　36-fold),　deep　tumor　penetration,　and　synergistic　antitumor　outcome　at　a　low　dose.　Thus,　this　simple　strategy　paves　the　way　for　the　green　development　of　efficient　photosensitizers.　©　2023　American　Chemical　Society.