In recent years, poly(ionic liquids) or polymerized ionic liquids (PILs) have gained significant attention. The combination of ionic liquids (ILs)’ unique properties with the macromolecular architecture of poly(ionic liquids) membranes (PILMs) is not only fascinating, but it also offers a way to develop new properties and functionalities for these innovative membrane materials in the field of membrane technology. Furthermore, PILMs provide a number of advantages over ionic liquids (ILs), including increased mechanical stability, chemical durability, spatial controllability, and processability. This paper presents a comprehensive overview of PILMs, including production processes, properties, and applications in industries such as electrolyte membranes for electrochemical devices, metal ions separation with polymer inclusion membranes (PIMs), CO₂ separation, and antibacterial membrane. Additionally, future potential and approaches for improving the performance of PILMs are highlighted.