Transforming Cellulose Into Functional Three‐Dimensional Structures

Abstract The impending energy crisis and climate change call for sustainable alternatives to petroleum‐based polymers for constructing three‐dimensional (3D) structures. As the most abundant biopolymer on Earth, cellulose offers structural versatility, biodegradability, and chemical tunability, making it an attractive platform for functional 3D architectures. Rather than providing a comprehensive survey of all structures and applications, this review focuses on recent advances in two major categories—liquid gels and porous materials—and explores their emerging roles in flexible electronics, thermal management, and water harvesting. The structure–property–function relationships and design principles underlying these materials are critically examined. Despite significant progress, challenges remain, including the difficulty of achieving elasticity and toughness comparable to synthetic polymers, limited scalability, and trade‐offs between functionality and sustainability. Looking forward, opportunities lie in dynamic crosslinking strategies, hierarchical structural design, and integration with advanced manufacturing techniques. These approaches will be crucial for advancing cellulose‐based 3D structures toward high‐performance, eco‐friendly solutions for next‐generation technology.