The　development　of　superior　heterogeneous　catalyst　for　hydrogen　(H2)　evolution　is　a　significant　feature　and　challenging　for　determining　the　energy　and　environmental　crises.　However,　the　dumping　of　numerous　lethal　colorants　(dye)　as　of　textile　manufacturing　has　fascinated　widespread　devotion-aimed　water　pollution　anticipation　and　treatment.　In　this　regard,　a　photocatalytic　H2　evolution　by　visible　light　using　low-dimensional　semiconducting　materials　having　pollutant　degradable　capacity　for　Rhodamine　B　dyes　(RhB)　has　been　anticipated　as　a　route　towards　environmental　aspect.　Here　we　fabricated　the　incorporation　of　organic　electron-rich　heterocyclic　monomer　2,6-dimethylmorpholine　(MP),　inside　electron-poor　graphitic　carbon　nitride　(g-CN)　semiconductor　by　solid-state　co-polymerization.　The　supremacy　of　copolymerization　process　was　successfully　examined　via　absorbent,　calculated　band　gap,　and　migration　of　electrons　on　the　photocatalytic　performance　of　as-constructed　CN-MP　copolymer.　The　density　functional　theory　(DFT)　calculation　provides　extra　support　as　evident　for　the　successful　integration　of　MP　into　the　g-CN　framework　by　this　means-reduced　band　gap　upon　co-polymerization.　The　hydrogen　evolution　rate　(HER)　for　g-CN　was　found　as　115.2　μmol/h,　whereas　for　CN-PM0.1　was　estimated　at　641.2　μmol/h　(six　times　higher).　In　particular,　the　pseudo-order　kinetic　constant　of　CN-MP0.1　for　photodegradation　of　RhB　was　two　times　higher　than　that　of　g-CN.　Results　show　an　important　step　toward　tailor-designed　and　explain　the　vital　role　of　the　D-A　system　for　the　rational　motifs　of　productive　photocatalysts　with　effective　pollutant　degradable　capability　for　future　demand.　©　2021　Elsevier　Inc.