Weak　light　absorption　of　common　Ir(III)　complexes　(e.　g.,　using　phenylpyridine　as　the　ligand)　has　hindered　their　applications　in　photocatalytic　hydrogen　generation　from　water　as　an　efficient　photosensitizer.　To　address　this　issue,　a　series　of　cyclometalated　Ir(III)　complexes　(Ir1–Ir5),　featuring　different　electron-donating　substituents　to　enhance　the　absorptivity,　have　been　synthesized　and　studied　as　photosensitizers　(PSs)　for　light-driven　hydrogen　production　from　water.　Ir6–Ir7　were　prepared　as　fundamental　systems　for　comparisons.　Electron　donors,　including　9-phenylcarbazole,　triphenylamine,　4,4′-dimethoxytriphenylamine,　4,4′-di(N-hexylcarbazole)triphenylamine　moieties　were　introduced　on　6-(thiophen-2-yl)phenanthridine-based　cyclometalating　(C^N)　ligands　to　explore　the　donor　effect　on　the　hydrogen　evolution　performance　of　these　cationic　Ir(III)　complexes.　Remarkably,　Ir4　with　4,4′-dimethoxytriphenylamine　achieved　the　highest　turn-over　number　(TON)　of　12　300　and　initial　turnover　frequency　(TOFi)　of　394　h−1,　with　initial　activity　(activityi)　of　547　000　μmol　g−1　h−1　and　initial　apparent　quantum　yield　(AQYi)　of　9.59　%,　under　the　illumination　of　blue　light-emitting　diodes　(LEDs)　for　105　hours,　which　demonstrated　a　stable　three-component　photocatalytic　system　with　high　efficiency.　The　TON　(based　on　n(H2)/n(PSr))　in　this　study　is　the　highest　value　reported　to　date　among　the　similar　photocatalytic　systems　using　Ir(III)　complexes　with　Pt　nanoparticles　as　catalyst.　The　great　potential　of　using　triphenylamine-based　Ir(III)　PSs　in　boosting　photocatalytic　performance　has　also　been　shown.　©　2022　Wiley-VCH　GmbH.