In this talk, I will discuss our recent work in studying the electronic, optical and ferromagnetic properties of emerging two-dimensional materials, and in developing them for novel electronic and photonic device applications. The first part of the talk will focus on discussing our recent research on the phonon-spin and phonon-electron coupling in ferromagnetic monolayer materials and its device applications. In the second part of the talk, I will discuss our work on developing black phosphorus for silicon integrated infrared sensing and imaging applications. Our work on characterizing the fundamental properties of black phosphorus and its application in high performance mid-infrared detector devices will be discussed. I will conclude with remarks on promising future research directions of low-dimensional material electronic and optical devices, and how they may impact future electronics and photonics technologies.