Efficient g-C3N4 photocatalysts have been successfully fabricated with different synthesis approaches. The XRD patterns confirm formation of g-C3N4 nanostructures. The freeze-dried samples exhibit the porous sheet like morphology, and FTIR analysis confirms the CN heterocycles. The zeta potential studies reveal that g-C3N4 nanostructures have more negative surface charge density. The catalysts degrade the organic pollutant Methylene Blue (MB) and Rhodamine B (RhB) in the presence of visible light irradiation. Freeze-dried g-C3N4 catalyst demonstrations expeditious photocatalytic degradation the MB (98.8 %) and RhB (98.6 %) dye in 40 min. The maximum photocatalytic degradation performance because of its low e-h recombination rate, wide range of absorption light, more photo-generated electrons and larger specific surface area. Trapping test confirms that photogenerated electrons will be the main reason for the efficient degradation of organic dyes (MB). The repeatability experiment results evidently confirm the prepared catalyst have high photo-stability. The obtained degradation efficiency results were competing with the many previously reported photocatalyst. These attempts will be useful to realize the photocatalytic mechanism of g-C3N4 with respective different synthesis routes.