Catalytic pathways to produce high carbon number compounds from benzyl phenyl ether require multiple steps to break the aryl etheric carbon–oxygen bonds; these steps are followed by energy-intensive processes to remove oxygen atoms and/or carbon–carbon coupling. Here, we show an upgrading strategy to transform benzyl phenyl ether into large phenolic (C₁₂–C₂₂) compounds by a one-step C–O breaking and C–C coupling catalyzed by metal triflates under a mild condition (100 °C and 1 bar). Hafnium triflate was the most selective for the desired products. In addition, we measured the effect of solvent polarity on the catalytic performance. Solvents with a polarity index of less than 3.4 promoted the catalytic activity and selectivity to C₁₂–C₂₂ phenolic products. These C₁₂–C₂₂ phenolic compounds have potential applications for phenol–formaldehyde polymers, diesel/jet fuels, and liquid organic hydrogen carriers.