<p>The rising worldwide energy demand and the pressing necessity to reduce greenhouse gas emissions have propelled the advancement of sustainable thermal energy storage (TES) systems. Phase Change Materials (PCMs) have emerged as a promising technology owing to their capacity to efficiently store and release latent heat. Organic phase change materials (PCMs), particularly paraffins and fatty acids, have benefits such as elevated energy density, chemical stability, and non-corrosiveness, rendering them appropriate for HVAC systems, renewable energy integration, electric vehicle battery thermal management, and cold chain logistics. Nonetheless, obstacles include inadequate thermal conductivity, phase separation, leakage, and environmental repercussions hinder their extensive implementation. This review offers an exhaustive examination of current developments in organic phase change materials (PCMs), addressing encapsulation techniques, nano-enhanced PCMs, hybrid composites, and form stabilization approaches. Particular focus is directed toward AI-driven material optimization, 3D-printed PCM composites, and advanced encapsulating techniques to improve thermal performance and scalability. This analysis delineates emerging research themes, encompassing sophisticated 3D-printed PCM composites, hybrid PCMs, machine learning-driven PCM design, and the incorporation of PCMs into smart energy grids and waste heat recovery systems. The results highlight the necessity for economical, eco-friendly, and high-efficiency PCM systems to facilitate sustainable energy storage and management. This paper addresses current issues and proposes future research paths, serving as a complete reference for researchers, engineers, and politicians focused on advancing sustainable thermal energy storage technology.</p> Graphical Abstract <p></p>