An efficient method has been developed for the green synthesis of alkylated quinolines via Cu‐TEMPO catalyzed dehydrogenation, and DEP/DES‐assisted benzylic C‐H functionalization followed by cross Rauhut‐Currier type reaction. The reaction mechanism is elucidated through control experiments and 1H NMR reaction monitoring. This transformation offers several advantages, including moderate to good yields of the desired products, mild reaction conditions, use of a cost‐effective metal catalyst, good functional group tolerance, and applicability to gram‐scale synthesis. Additionally, the synthetic utility and the photophysical properties of the synthesized alkylated quinoline derivatives were investigated.