Anisotropic 2D materials have been established as a promising candidate for future optoelectronic applications in the previous chapters. But, what makes them suitable for these applications? 2D materials have the capability to host a rich set of electronic states that differ considerably from their bulk counterparts, which is attributed to reduced dielectric screening and quantum confinement. In the recently discovered anisotropic 2D materials this ability is further enhanced due to further confinement in one direction. This results in a wide variety of many-body effects and complexes that have crucial applications for future optoelectronic device applications. These many-body complexes have now been experimentally detected and the high binding energy of these complexes makes them interesting for various applications, even at room temperature. This chapter focusses on addressing the fundamental physics behind light–matter interactions at the 2D limit in the anisotropic materials. It addresses the key fundamental properties of anisotropic 2D materials such as crystal structure, electronic band structure, many-body system behaviour, excitonic effects and subsequent optical properties that make these materials suitable for various future electronic, optoelectronic and miniature device fabrication applications. The chapter highlights their key properties and demonstrated applications that have been recently experimentally established, making these anisotropic 2D materials an interesting avenue for future miniaturized device fabrication and applications.