This review provides a comprehensive analysis of the current state of research on graphitic carbon nitride (g-C₃N₄)-based photocatalysts. g-C₃N₄ is a promising photocatalyst due to its unique band structure, excellent stability, and environmental friendliness. The review discusses various strategies to enhance the photocatalytic performance of pristine g-C₃N₄, including creating heterojunctions, doping with non-metallic and metallic materials, co-catalyst loading, tuning catalyst morphology, metal deposition, and nitrogen-defect engineering. It also highlights characterization techniques used to understand the structural and physicochemical features of g-C₃N₄-based catalysts, as well as their applications in photocatalytic degradation and hydrogen production. The review investigates the effect of operational parameters on the catalytic activity and efficiency of g-C₃N₄-based catalysts, shedding light on the key factors influencing their performance. It also provides insights into the photocatalytic pathways and reaction mechanisms involving g-C₃N₄-based photocatalysts. The review identifies research gaps and challenges in the field and presents prospects for the development and utilization of g-C₃N₄-based photocatalysts. Overall, this comprehensive review provides valuable insights into the synthesis, characterization, applications, and prospects of g-C₃N₄-based photocatalysts, offering guidance for future research and technological advancements in this rapidly growing field. The review also discusses various modification approaches to enhance the performance of pure g-C₃N₄, including heterojunctions, doping, co-catalyst loading, tuning morphology, metal deposition, and defect engineering. The review highlights the synthesis methods of g-C₃N₄-based photocatalysts, their applications in environmental remediation, and the characterization techniques used to understand their properties. It also describes the mechanisms and factors influencing the photocatalytic performance of g-C₃N₄-based photocatalysts in organic pollutant degradation, providing insights into the identification of key intermediates and reactive species involved in the photocatalytic degradation processes. The review further investigates the strategies employed to enhance the efficiency and selectivity of g-C₃N₄-based photocatalysts, including the utilization of metal cocatalysts, co-doping techniques, heterojunction formation, and surface modification. Additionally, the review assesses the application of g-C₃N₄-based photocatalysts in hydrogen production through water splitting, evaluating their performance in terms of hydrogen evolution rate, stability, and selectivity, while discussing the underlying mechanisms of photogenerated charge separation and transfer. The review also discusses the modification of g-C₃N₄ by creating heterojunctions, including Type-I and Type-II heterojunctions, p-n heterojunctions, Z-scheme and S-scheme heterojunctions, and the use of metal oxides and metalThis review provides a comprehensive analysis of the current state of research on graphitic carbon nitride (g-C₃N₄)-based photocatalysts. g-C₃N₄ is a promising photocatalyst due to its unique band structure, excellent stability, and environmental friendliness. The review discusses various strategies to enhance the photocatalytic performance of pristine g-C₃N₄, including creating heterojunctions, doping with non-metallic and metallic materials, co-catalyst loading, tuning catalyst morphology, metal deposition, and nitrogen-defect engineering. It also highlights characterization techniques used to understand the structural and physicochemical features of g-C₃N₄-based catalysts, as well as their applications in photocatalytic degradation and hydrogen production. The review investigates the effect of operational parameters on the catalytic activity and efficiency of g-C₃N₄-based catalysts, shedding light on the key factors influencing their performance. It also provides insights into the photocatalytic pathways and reaction mechanisms involving g-C₃N₄-based photocatalysts. The review identifies research gaps and challenges in the field and presents prospects for the development and utilization of g-C₃N₄-based photocatalysts. Overall, this comprehensive review provides valuable insights into the synthesis, characterization, applications, and prospects of g-C₃N₄-based photocatalysts, offering guidance for future research and technological advancements in this rapidly growing field. The review also discusses various modification approaches to enhance the performance of pure g-C₃N₄, including heterojunctions, doping, co-catalyst loading, tuning morphology, metal deposition, and defect engineering. The review highlights the synthesis methods of g-C₃N₄-based photocatalysts, their applications in environmental remediation, and the characterization techniques used to understand their properties. It also describes the mechanisms and factors influencing the photocatalytic performance of g-C₃N₄-based photocatalysts in organic pollutant degradation, providing insights into the identification of key intermediates and reactive species involved in the photocatalytic degradation processes. The review further investigates the strategies employed to enhance the efficiency and selectivity of g-C₃N₄-based photocatalysts, including the utilization of metal cocatalysts, co-doping techniques, heterojunction formation, and surface modification. Additionally, the review assesses the application of g-C₃N₄-based photocatalysts in hydrogen production through water splitting, evaluating their performance in terms of hydrogen evolution rate, stability, and selectivity, while discussing the underlying mechanisms of photogenerated charge separation and transfer. The review also discusses the modification of g-C₃N₄ by creating heterojunctions, including Type-I and Type-II heterojunctions, p-n heterojunctions, Z-scheme and S-scheme heterojunctions, and the use of metal oxides and metal