The regioselective aromatic C-H bond functionalization has become a viable approach for intricate molecular targets due to their high atom efficiency and development of sustainable chemistry . Nevertheless, the precise functionalization of the aromatic C-H bond continues to pose a challenge due to the subtle differences in reactivity among the multiple C-H bonds present within the substrate . Heading down this path, the highly notable electrophilic aromatic substitution, also recognized as the Friedel-Crafts (FC) reaction (Scheme 1A) , finds extensive utility. According to the FC reactions, electron-rich aromatic compounds yield products in a nearly equimolar mixture of ortho/para-selectivity and electron-deficient aromatics generate exclusively meta-selective products upon encountering electrophilic species. These reactions are both induced by the electron-density aspect, which is contingent upon the specific substituents within the molecule, manifesting either in the ortho/para-or meta-position. Therefore, the challenge lies in altering the regioselectivity pattern, explicitly focusing on para-C-H bond functionalization of electron-poor arenes and meta-C-H bond functionalization of electron-rich arenes. To address this, contemporary chemists have explored this captivating field and developed photocatalytic methods (4) and transition-metal catalytic techniques for achieving metaselective C-H bond functionalization in electron-rich arenes. Within these studies, they selected a suitable additive (NHCs in the case of photocatalysis) or ligand (L-shaped ligands in the context of transition-metal catalysis) to hinder the ortho/para-positions, thereby ensuring exclusive metaselectivity. Nevertheless, it is worth noting that all these methodologies have limitations, including the use of non-recyclable catalysts, stoichiometric additives, and multi-step reactions. On the other hand, para-selective functionalization is also known; however, regioselectivity has predominantly been governed by the electron-rich directing group approach or formulating ligands with a templating effect in the presence of homogeneous catalysis . While these approaches yielded effective product outcomes, they were not without their share of drawbacks , including nonrecyclable catalysts, pre-installation of specialized directing groups, and the involvement of multistep reactions. Hence, achieving para-selective functionalization of electron-deficient arenes, as well as for an undirecting strategy, remains a challenge in organic synthesis which is yet to overcome . In this aspect, designing single metal atom catalysts (SACs) will be highly effective due to their unique reactivity and reusability, bridging heterogeneous and homogeneous catalysis. This type of catalyst has the maximum atom utilization efficiency and thanks to advanced characterizations, structure-activity relationships with the active sites are also possible. However, the presence of the support materials onto which the transition metal atoms are deposited in SAC, plays a crucial role (like the ligands in organometallic complexes) and facilitates charge transfer, enhancing photocatalytic reactivity . In this aspect, polymeric carbon nitrides (PCN), as a support material, have recently become an invaluable support to design robust SACs due to their exceptional stability, high surface area, and tunable chemical properties, ultimately enhancing their catalytic activity, and enabling precise control over their reactivity . It is important to highlight that, from a sustainability perspective, nitrogen-substituted carbon and polymeric carbon nitrides (PCN) emerge as promising green photocatalysts due to their reliance on abundant elements during the design and preparation phases . Considering this, tremendous efforts have been paid to achieve transformations such as small molecule activations . However, their application into regioselective C-H bond functionalization is still in its infancy. To fill this gap, an atomically dispersed Cu photocatalyst has been designed by adding copper to a nanocrystalline PCN support with a typical distance of approximately 2 Å. With the photocatalyst design, our objective was to realize a para-selective aromatic C-H bond trifluoromethylation since the inclusion of a trifluoromethyl (-CF3) group within a molecule imparts heightened pharmacokinetic attributes, encompassing enhancements in metabolic stability, permeability, and affinities for protein binding . Compounds containing a trifluoromethyl group (-CF3), particularly aromatic and heteroaromatic molecules, are frequently encountered in diverse domains such as pharmaceuticals, drugs, agrochemicals, organic dyes, and polymers . Therefore, the introduction of this motif and its unique characteristics highlights the achievements of chemical synthesis, especially given its notable absence in nature. Our hypothesis for achieving this high regioselectivity involved the use of an atomically dispersed Cu photocatalyst, which plays a crucial role in a regio-determining step by interacting with the aromatic substrate in an η 2 fashion. Sterically hindering the ortho-and meta-positions (Scheme 1B, TS-I) enables the alternate regioselective functionalization of aromatic C-H bonds in electron-poor aromatic compounds. A thorough examination of the structure and mechanisms confirms the cooperative behavior of metal centers in neighboring sites, facilitating the efficient activation of substrates through a dynamic bridge-coupling mechanism.