  Material science is an important foundation of modern society development,
covering significant areas like chemosynthesis and metamaterials. Click
chemistry provides a simple and efficient paradigm for achieving molecular
diversity by incorporating modified building blocks into compounds. In
contrast, most metamaterial designs are still case by case due to lacking a
fundamental mechanism for achieving reconfigurable thermal conductivities,
largely hindering design flexibility and functional diversity. Here, we propose
a universal concept of click metamaterials for fast realizing various thermal
conductivities and functionalities. Tunable hollow-filled unit cells are
constructed to mimic the modified building blocks in click chemistry. Different
hollow-filled arrays can generate convertible thermal conductivities from
isotropy to anisotropy, allowing click metamaterials to exhibit adaptive
thermal functionalities. The straightforward structures enable full-parameter
regulation and simplify engineering preparation, making click metamaterials a
promising candidate for practical use in other diffusion and wave systems.
