In recent years, the field of dual photocatalysis has become an increasingly popular tool for the functionalization of organic substrates under mild operative conditions. Single-atom heterogeneous catalysts (SACs), where the metal atoms are stabilized by means of properly structured photoactive supports, are currently one of the frontiers of this research field. To this end, Carbon Nitrides (CNs) have emerged as ideal two-dimensional semiconducting supports, capable of stabilizing single metal sites (for instance: nickel, iron, among other) through nitrogen-rich structures. This Concept highlights the recent advances in the synthesis of carbon nitride-based SACs and their applications in light-driven dual-catalytic processes, also providing forward-looking opportunities within this research area.