<p>Redox-active organic polymers (RAOPs) have emerged as a versatile and sustainable class of materials for next-generation energy technologies. Their unique ability to undergo reversible redox reactions, combined with lightweight, flexible, and tunable structures, makes them highly suitable for diverse applications. This review presents a comprehensive overview of recent advancements in RAOPs for energy storage, energy harvesting, and catalysis. In storage systems, RAOPs offer promising alternatives to inorganic materials in batteries and supercapacitors, including all-organic configurations. Their integration into organic photovoltaics and thermoelectric devices highlights their role in efficient energy conversion and hybrid energy systems. In catalysis, RAOPs enable enhanced performance in hydrogen evolution, CO₂ reduction, and photocatalytic processes. We discuss molecular design strategies, structure–property relationships, and synthetic approaches that govern RAOP functionality, while also addressing key challenges such as stability, conductivity, and scalability. With growing interest in eco-friendly, high-performance materials, RAOPs hold transformative potential to advance sustainable and self-powered energy systems.</p>