The synthesis of (p-chlorophenyl)diphenylmethane from p-chlorobenzaldehyde and benzene catalyzed by the super acid Nafion-H is investigated in a high-temperature/high-pressure process window using both batch and continuous-flow conditions. The reaction is initially studied under sealed-vessel batch environments using both microwave and conventional heating. The optimized conditions are then translated to a continuous-flow approach applying Nafion-H in a packed-bed reactor. Under both sets of conditions, the triarylmethane is obtained within a few minutes in high yields.