This　work　incorporates　a　variety　of　conjugated　donor-acceptor　(DA)　co-monomers　such　as　2,6-diaminopurine　(DP)　into　the　structure　of　a　polymeric　carbon　nitride　(PCN)　backbone　using　a　unique　nanostructure　co-polymerization　strategy　and　examines　its　photocatalytic　activity　performance　in　the　field　of　photocatalytic　CO2　reduction　to　CO　and　H-2　under　visible　light　irradiation.　The　as-synthesized　samples　were　successfully　analyzed　using　different　characterization　methods　to　explain　their　electronic　and　optical　properties,　crystal　phase,　microstructure,　and　their　morphology　that　influenced　the　performance　due　to　the　interactions　between　the　PCN　and　the　DPco-monomer.　Based　on　the　density　functional　theory　(DFT)　calculation　result,　pure　PCN　and　CNU-DP15.0　trimers　(interpreted　as　incorporation　of　the　co-monomer　at　two　different　positions)　were　extensively　evaluated　and　exhibited　remarkable　structural　optimization　without　the　inclusion　of　any　symmetry　constraints　(the　non-modified　sample　derived　from　urea,　named　as　CNU),　and　their　optical　and　electronic　properties　were　also　manipulated　to　control　occupation　of　their　respective　highest　occupied　molecular　orbital　(HOMO)　and　lowest　unoccupied　molecular　orbital　(LUMO).　Also,　co-polymerization　of　the　donor-acceptor　2,6-diamino-purine　co-monomer　with　PCN　influenced　the　chemical　affinities,　polarities,　and　acid-base　functions　of　the　PCN,　remarkably　enhancing　the　photocatalytic　activity　for　the　production　of　CO　and　H-2　from　CO2　by　15.02-fold　compared　than　that　of　the　parental　CNU,　while　also　improving　the　selectivity.