**Abstract**

Since the discovery of intrinsic long-range magnetic order in two-dimensional (2D) layered magnets, e.g., Cr2Gr2Te6 and CrI3 in 2017, it has attracted intensive studies of new physical phenomena in these systems down to a few atomic layers, especially, their magnetism ground states at finite temperatures. Recently, the lightmatter interactions in 2D magnets, including light absorption, emission, scattering, et al., have gradually drawn researchers' attention and are current active research directions. The mechanism of light-matter interactions in 2D magnets challenges the knowledge of materials physics, which drives the rapid development of materials synthesis and device applications. In this chapter, an overview of crystal structures, magnetic properties, and electronic band structures is presented. More importantly, the current status of light-matter interactions in 2D magnets will be discussed, which provides a solid basis for understanding novel physical phenomena in 2D magnets and proves the importance of tuning the magnetic, electronic, and vibrational degrees of freedom for designing novel 2D magnet-based device applications.

**Keywords:** 2D magnets, light-matter interaction, magnetism, light emission, light scattering
