Thermoelectrics are an important class of technology that harvest electric power directly from heat sources. In this review, I aim to comprehensively summarize the fundamental strategies for the realization of high-performance thermoelectric materials. In addition, multinary materials have attracted considerable attention for energy applications due to their tunable physical properties. Here, I describe thermoelectric properties of multinary thermoelectric material Cu2ZnSnS4 bulk single crystal. The progresses in multinary materials will promote the use of thermoelectric technology to play a positive role in future energy solutions.