Conventional condenser-based cooling systems rely on refrigerants and are constrained by their large size and complex structures. With the rapidly growing demand for cooling technologies, the environmental concerns associated with refrigerant-induced global warming are becoming increasingly serious. In this context, solid-state cooling technologies—characterized by their high efficiency without the use of refrigerants—are gaining attention as eco-friendly alternatives for next-generation cooling. Solid-state cooling controls heat directly through the intrinsic thermodynamic properties of solid materials, eliminating the need for conventional refrigerants. Key mechanisms include the thermoelectric effect and various caloric effects, such as electrocaloric, magnetocaloric, barocaloric, and elastocaloric effects. These technologies offer advantages, such as compactness, structural simplicity, high reliability, and environmental sustainability. Our laboratory conducts fundamental research on solid-state cooling technologies, focusing on both thermoelectric cooling and multicaloric cooling that combine two or more caloric effects. Our research spans from the discovery of new materials to the design of devices and systems, aiming to build a comprehensive foundation for this emerging field. Ultimately, we strive to lead innovation in thermal management across various industries while contributing to the development of sustainable, next-generation cooling solutions.