Short-lived　shallow　trapping　states　in　photocatalysts　created　from　polymeric　semiconductors　impedes　the　effective　use　of　charge　carriers,　leading　to　a　decrease　in　the　solar-to-hydrogen　conversion　efficiency　of　covalent　triazine　frameworks　(CTF).　In　this　study,　methylene-modified　covalent　triazine　frameworks　(M−CTF)　with　increased　structural　distortion　were　synthesized　through　a　dynamic　trimerization　reaction　of　cyano　groups　using　the　precursors　of　1,4-terephthalonitrile　and　1,4-phenylenediacetonitrile.　The　optimal　M−CTF　catalyst　obtained　in　this　approach　showed　persistent　shallow　trapping　states　through　n-π*　electronic　transitions,　leading　to　a　noticeable　red-shift　in　the　light　absorption　edge　to　600　nm.　Femtosecond　transient　absorption　spectroscopy　verified　the　existence　of　shallow　trapping　states　with　extended　lifetimes　(1103.8　ps)　in　M−CTF.　The　distorted　structure　promote　increased　involvement　of　photo-induced　electrons　in　reducing　water　to　generate　H2,　leading　to　a　substantial　improvement　in　the　ability　of　M−CTF　to　catalyze　the　production　of　H2.　M−CTF　sample　loaded　with　Pt　cocatalysts　exhibited　an　impressive　efficiency　of　10.1　mmol·g−1·h　−1　in　producing　H2　via　photocatalysis　under　visible　light　(λ　＞　420　nm),　marking　a　tenfold　improvement　compared　to　the　original　CTF.　The　findings　underscore　the　significance　of　structural　distortion　in　CTF　for　achieving　long-lasting　shallow　trapping　states,　leading　to　improved　photocatalytic　efficiency.　©　2024　Elsevier　Inc.