2D materials have attracted great interest because of their unique and excellent physical properties which promise various electronic and photonic applications. In this talk, I will introduce our recent research on 2D materials, based on a novel concept of “2.5 dimensional materials” that expands the possibility of 2D materials. The control over the number of layers, stacking angle, stacked materials as well as the combination with other low dimensional materials offers new opportunity to obtain attractive physical properties and to develop practical applications.