This chapter addresses using non-oxide two-dimensional nanomaterials for the photoelectrocatalytic reduction of carbon dioxide (CO₂) in an aqueous medium. These photocatalysts have been receiving significant attention in complex reactions that involve multiple steps, such as CO₂ reduction and water splitting, due to their catalytic characteristics, including highly accessible active sites and abundant surface defects. These abundant surface defects enhance the adsorption of CO₂ and H₂O, tunable electronic features, and excellent charge separation properties. Among the diverse non-oxide two-dimensional photocatalysts reported in the literature, this chapter scrutinizes the two-dimensional transition-metal dichalcogenides (TMDC), nitrides, carbonitrides, metal–organic frameworks (MOFs), and heterojunctions of these catalysts. This investigation is intended to stimulate a novel pathway for researchers to improve the design of materials by harnessing the exceptional structural, optical, and electronic properties impacting the selectivity, activity, and stability of catalysts for successful application in the CO₂ reduction. The elucidation of the physical and catalytic properties of two-dimensional nanomaterials opens new opportunities for industrial applications and the reduction of environmental issues, resulting in a positive impact on the economy.