Photocatalysis processes have attracted much attention in recent decades because of their potential for environmental purification and converting solar photo-energy into chemical energy. It is important to design novel catalysts with high photocatalytic efficiency and seek for new applications, as well as to understand deeply the mechanism. This chapter gives a brief overview of the promising polymeric graphene and g-C3N4 based photocatalytic materials, including their history, construction, properties, and applications. In addition, the origin and classification of Z-scheme photocatalytic systems, the engineering of Z-schemes, together with the verification methods are summarized. We also introduce the terms of plasmonic photocatalysis and roles of surface plasmon resonance in the physicochemical properties and photocatalytic activity enhancement. Moreover, applications in photosynthesis of biomass-derivatives and a brief mechanistic discussion are presented. Finally, this chapter highlights the ongoing challenges and opportunities for the future development of photocatalysis.