Integrating　selective　organic　transformation　and　hydrogen　(H2)　evolution　in　one　photoredox　reaction　system　is　one　of　the　most　sustainable　and　promising　approaches　to　efficiently　produce　solar　fuels　and　chemicals　by　simultaneously　utilizing　photogenerated　electrons　and　holes.　Herein,　through　the　cation-exchange　engineering　method,　the　nanoleaf-like　Pd/CdS　composites　are　gingerly　fabricated　for　visible-light-driven　receptor-free　dehydrogenation　of　1,2,3,4-tetrahydroisoquinoline　(THIQ)　to　3,4-dihydroisoquinoline　(DHIQ)　and　H2　under　ambient　conditions.　The　optimized　electronic　structure　endows　Pd/CdS　with　a　narrow　band　gap　and　suitable　energy　band　positions,　thus　facilitating　the　light　harvesting　as　well　as　the　separation　and　transfer　of　photoexcited　charge　carriers.　Consequently,　the　Pd/CdS　exhibits　significantly　improved　photoredox　activity　compared　to　bare　CdS.　In-situ　Fourier-transform　infrared　spectroscopy　and　electron　paramagnetic　resonance　spectroscopy　track　the　progression　of　reaction　intermediates　during　such　a　dual-functional　photoredox-catalyzed　system,　revealing　that　the　carbon-centered　radical　is　the　key　reaction　intermediate　in　this　reaction　process.　It　is　anticipated　that　this　work　would　guide　the　rational　utilization　of　CdS-based　materials　to　enable　simultaneous　photochemical　coupling　of　organic　transformation　and　H2　evolution.