This paper describes our approach to render active functions to microporous crystal 12CaO(.) 7Al(2)O(3) (C12A7), which is known as a major constituent of alumina cement, utilizing nanostructure inherent to crystal lattice and active negative ions, O- or H-. The preparation of C12A7 encaging abundant O- ions is shown along with its unique properties. Light-induced conversion into a persistent electronic conductor was discovered for H--bearing C12A7.