The emerging class of low symmetry 2D materials, which include black phosphorus, its isoelectronic materials such as the monochalcogenides of Group IV elements and other layered materials with reduced in-plane symmetry, exhibit strong in-plane anisotropy in their optical and phonon properties that allow for the realization of conceptually new electronic and photonic devices. High mobility, narrow gap BP thin film (0.3 eV in bulk), for example, fill the energy space between zero-gap graphene and large-gap transition metal dichalcogenides, making it a promising material for mid-infrared wavelength infrared optoelectronics. Here, we will first present our work in understanding the fundamental electronic and optical properties of low-symmetry 2D materials such as black phosphorus and rhenium diselenide using a newly developed scanning ultrafast electron microscopy (SUEM) technique and photoluminescence spectroscopy. A few novel photonic device concepts will then be discussed that utilize these new materials, particularly for applications in the infrared wavelength range. We will also discuss about promising future research directions of low-symmetry optoelectronic devices based on anisotropic 2D materials and how their novel properties is expected to benefit the next-generation photonics technologies.