Four　new　metal-free　organic　photosensitizers　featuring　either　a　mono-anchoring　donor–π–acceptor　(D–π–A)　or　di-anchoring　donor–(π–acceptor)2　(D(–π–A)2)　architecture　containing　a　spirobifluorene　or　spiro[fluorene-9,9′-xanthene]　central　donor　core　was　prepared.　These　photosensitizers　were　subsequently　tested　for　their　efficiency　in　the　photocatalytic　production　of　H2,　in　combination　with　a　Pt/TiO2　catalyst.　Additionally,　electrochemical,　photophysical,　and　computational　studies　were　conducted.　The　computational　studies　were　specifically　carried　out　to　ascertain　the　electronic　distribution　within　the　photosensitizers.　The　influence　of　the　molecular　design　on　the　efficiency　of　H2　production　was　examined.　The　di-anchoring　photosensitizers　notably　amplified　the　spectral　response　in　the　visible　light　region,　reduce　aggregation　on　TiO2　and　enhanced　charge　transfer.　Among　the　fabricated　photocatalytic　systems,　the　di-anchoring　photosensitizers　exhibited　superior　photocatalytic　efficiency　compared　to　their　mono-anchoring　counterparts.　Among　all　the　photosensitizers,　the　spiro[fluorene-9,9′-xanthene]-based　di-anchoring　photosensitizer　X2　possessing　photocatalytic　system　demonstrated　remarkable　performance,　producing　406.3　μmol　(10.07　mL)　of　hydrogen　over　a　period　of　47　h　under　blue　light　irradiation.　This　performance　corresponds　to　a　turnover　number　(TON)　of　6674,　a　turnover　frequency　(TOFi)　of　445　h−1,　an　initial　hydrogen　production　activity　(activityi)　of　278140　and　an　apparent　quantum　yield　(AQYi%)　of　4.762.　The　bulky　spiro[fluorene-9,9′-xanthene]　component　endowed　the　photosensitizers　with　photostability,　as　confirmed　by　their　high　hydrogen　production　efficiency　over　152　h　of　extended　irradiation,　yielding　12.69　mL　of　hydrogen.　This　study　revealed,　for　the　first　time,　that　the　bulky　spiro-fluorene　structure　contributes　positive　synergistic　effects　to　hydrogen　production.　It　demonstrates　that　dibranched　photosensitizers　containing　spiro-fluorene　are　promising　candidates　for　achieving　high　and　stable　hydrogen　production　activity.　©　2024　Elsevier　Ltd