Display omitted In the present work, we designed and synthesized a cationic cyano-substituted p-phenylenevinylene derivative (PPTA), which can form supramolecular assemblies through electrostatic interaction with a type of polyelectrolyte material anionic guar gum (GP5A). A polyelectrolyte-based artificial light-harvesting system (LHS) was constructed by selecting a fluorescent dye sulforhodamine 101 (SR101) that matched its energy level as an energy acceptor. The energy harvested by the acceptors was used in the aqueous phase cross dehydrogenation coupling (CDC) reaction with a yield of up to 87%. In addition, the general applicability of polyelectrolyte materials to build artificial LHS was demonstrated by three other polyelectrolyte materials sodium polyphenylene sulfonate (RSS), sodium carboxymethyl cellulose (CMC), and sodium polyacrylate (PAAS), in which the CDC reaction was also carried out by these three LHSs and obtained high yields. This work not only provides a new method to construct LHSs by using polyelectrolyte materials, but also provides a beneficial exploration for further applying the energy harvested in LHSs to the field of photocatalysis in an aqueous solution.