Porous cages have emerged as highly attractive components for the development of stimuli-responsive smart materials, owing to their well-defined three-dimensional architectures and exceptional host-guest chemistry. Their excellent solubility and processibility facilitate seamless integration into various material forms, including thin films, membranes, and gels. This perspective highlights strategies for constructing porous-cage-based smart materials, showcasing their transformative applications in areas like tunable separation, luminescent materials, and soft actuators. It emphasizes the key role of host-guest interactions in empowering “smartness” to these systems, driven by structural and property changes triggered by guest molecules. While various synthetic limitations remain, the scalability and mechanistic understanding of these materials, fabrication techniques, and interdisciplinary approaches are unlocking pathways to overcome these challenges. We envision that future developments will position porous cages as key enablers of next-generation smart materials, driving groundbreaking innovations in science and technology.