Graphitic　carbon　nitride,　g-C3N4　(CN)　is　regarded　as　an　excellent　metal-free　semiconductor　known　for　its　potential　solar　fuel　generation　and　pollutant　degradation.　In　this　study,　a　carbon　richer　substance,　(5,8-dibromoisoquinoline　(BQ))　was　used　to　feed　its　catalytic　function　through　conventional　copolymerization　(molecular　doping)　process　at　550　degrees　C　under　a　nitrogen　atmosphere.　The　incorporation　of　BQ　monomer　in　the　triazine　oligomers　of　CN　in　turn　enhanced　the　specific　surface　area,　thereby,　improving　the　lifespan　of　photoexcited　charge　carriers,　decreasing　the　charge　recombination　rate,　energy　bandgap,　and　altering　the　optoelectronic　characteristics　of　CN.　On　average,　the　rate　of　hydrogen　(H-2)　production　over-optimized　10BQ/CN　was　710.1　mu　mol/h　much　superior　and　10　times　higher　than　that　of　pure　CN　(71.9　mu　mol/h).　Particularly,　the　kinetics　of　the　photocatalytic　degradation　of　RhB　over　10BQ/CN　followed　pseudo-order　kinetics　and　the　rate　constant　was　three　times　larger　than　pure　CN.　Our　results　illustrate　the　crucial　importance　of　conjugated　monomers　in　improving　photocatalysis　process　for　future　energy　demand　by　providing　key　steps　towards　sustainable　energy　production.