Over the past decade, the plasmonics of graphene and black phosphorus (BP) were widely recognized as promising media for establishing linear and nonlinear light-matter interactions. Compared to the conventional metals, they support significant light-matter interaction of high efficiency and show undispersed optical properties. Furthermore, in contrast to the conventional metals, the plasmonic properties of graphene and BP structure can be tuned by electrical and chemical doping. In this review, a deep attention was paid toward the second- and third-order nonlinear plasmonic modes of graphene and BP. We present a theoretical framework for calculating the lifetime for surface plasmons modes of graphene and BP assisted by the coupled mode theory. The effect of the Fermi energy on the second-order and third-order nonlinear response is studied in detail. We survey the recent advances in nonlinear optics and the applications of graphene and BP-based tunable plasmonic devices such as light modulation devices, switches, biosensors, and other nonlinear photonic devices. Finally, we highlight a few representative current applications of graphene and BP to photonic and optoelectronic devices.