The growing energy crises and accumulating organics in water have caused significant threats to the economy and environment in the current time. To minimize the impact of these problem, here we established a 2D/2D interaction between MoS2 and g-C3N4 through simple hydrothermal and calcination processes and was further loaded with Au nanoparticles. The visible light driven photocatalysis was arrived by splitting water and degrading hazardous pollutant in wastewater. The large surface to surface interaction exceedingly increased the charge transfer and separation for highly speedy photocatalysis. About 220 μmol H2 was available from 2Au/9MS/CN nanocomposite in 1 h which was 24.44 times higher than the amount available from bare g-C3N4. Further, all the photocatalysts delivered acceptable eradication activity for 2-chlorphenol and 68% pollutant was removed in 1 h. The highly accelerated photocatalysis with 2Au/9MS/CN nanocomposite is related to the extended visible light purchasing due to the surface plasmon resonance of the Au metal and enhanced charge separation arrived from the well-established 2D/2D heterojunction. We hope that this work will attract major attention of the researchers towards the preparation of dimension-matched 2D/2D heterojunctional nanocomposites for energy production and eradication of organics from water.