BiOCl/CdS/g-C3N4 heterostructure and related photcatalysts have been designed successfully by decorating the 2D organic graphitic carbon nitride (g-C3N4) and inorganic bismuth oxychloride (BiOCl) semiconductor nanosheets with cadmium sulphide (CdS) nanoparticles. We have employed solvothermal cum co-precipitation method to fabricate the photocatalysts. The morphologies, optical and electronic properties of the photocatalysts have been studied by spectroscopic and microscopic methods. The BiOCl/CdS/g-C3N4 photcatalyst shows remarkably high visible-light-driven photocatalytic activity for the degradation of rhodamine B (RhB) with first order rate constant of 0.09 min(-1). The observed photodegradation activity is of the order, BiOCl/CdS/g-C3N4 > CdS/g-C3N4 > BiOCl/g-C3N4 > g-C3N4. Radical scavenging experiments show that superoxide radicals (O-center dot-(2)) and holes (h(+)) are more active species in the photodegradation of RhB than hydroxyl radicals ((OH)-O-center dot). This study reveals that morphology and synergic interactions of BiOCl and g-C3N4 nanosheets with CdS nanoparticles are crucial to separate the photogenerated electron-hole pairs and enhance the photocatalytic activity for RhB degradation.