After optimizing the reaction conditions, the scope of this reaction was investigated by applying it to different aromatic compounds (Scheme 2). Initially, in alignment with our hypothesis, commonly recognized electron-deficient aromatic compounds such as trifluoro-and cyanobenzene were examined and yielded a para-selective product up to the yield of 50-44% with a selectivity ratio of 5:1-4:1(3b-c). In addition to derivatives of trifluoro-and cyano-benzene, other electron-poor arenes such as azobenzene, 4-methoxy azobenzene, and phenylsulfoxide also produced their respective products with satisfactory yield and selectivity (3d-f). The obtained results revealed that the efficacy of electron-withdrawing groups may be attributed to the plausible interaction between polar groups present in the substrate and the photocatalyst throughout the course of the reaction. These interactions played a pivotal role in influencing the overall reaction pathway, thereby serving as critical factors for comprehending the mechanistic intricacies inherent in the photochemical process. Further introduction of various substitutions at different positions on the aromatic ring of electron-poor arenes, including -halide and -alkyl groups, did not compromise the yield and selectivity (3g-m). Likewise, substituted electron-deficient arenes, particularly those containing nitro groups, exhibited favorable reactivity, underscoring the consistent engagement of these substituents in interaction phenomena with the photocatalyst. In addition to its effective application to electron-deficient aromatic compounds, this approach has been successfully extended to electron-rich molecules. In this regard, it is worth noting that the regioselective trifluoromethylation of electron-rich arenes was previously attained by several research groups by using homogeneous photoredox catalysis , transition-metal catalysis or electrochemical processes . However, these methods suffer from the use of non-recyclable photocatalysts, pre-functionalized arene, and stoichiometric use of additives. Following our reaction conditions, a variety of anisole derivatives produced para-selective trifluoromethylated products with exceptional selectivity (3n-o). Unlike traditional electrophilic aromatic substitution reactions that yield a mixture of ortho and para products (nearly 1:1 ratio), our designed photocatalyst afforded specifically para-selective products under these reaction conditions. Small molecules such as phenol, fluorobenzene, and iodobenzene also produced trifluoromethylated products with high selectivity (3p-r). While our devised reaction conditions facilitated the smooth generation of corresponding products from oxygenated, halogenated, and alkylated arenes, chlorobenzene exhibited sluggish reactivity under the reaction conditions, attributable to the higher electron affinity of chlorine relative to fluorine and iodine. Furthermore, electronically neutral molecules such as benzene, isopropyl, and tert-butyl benzene demonstrated robust reactivity under our reaction conditions, yielding the corresponding products up to the yields of 50-52% and selectivity of 10:1 (3s-u). To our observation, different protected and unprotected N-alkyl anilines (3v-z), afforded a series of aryl trifluoromethylated products in good to excellent yields (53-83%), maintaining the high regioselectivity (up to 20:1). A notable observation was made when heterocyclic ring with an aromatic amine was employed, selective trifluoromethylation occurred at the C-2 position of the thiophene moiety, driven by the elevated electron richness of the heterocycle (3aa; 56%). Scheme 2. Trifluoromethylation substrate scope. Reaction conditions: 1 (0.2 mmol, 1 equiv.), 2a (0.3 mmol, 1.5 equiv.), catalyst (5 mg), MeCN (0.13 M) irradiated under blue LED irradiation for indicated time at room temperature. a CF3SO2Cl was used instead of 2a.