A new solution-phase methodology microwave-assisted for improving the Pictet-Spengler reaction in the synthesis of the tetrahydroisoquinoline and beta-carboline derivatives has been reported. This methodology was applied to obtain a small library of tetrahydroisoquinoline and beta-carboline derivatives using L-Dopa, dopamine, and tryptophan, as well as a variety of commercially available aldehydes as starting material. The use of such nonconventional reaction conditions reveals several features like a short reaction time compared to conventional eating, ease of isolation of the products after work-up, and improvement of the yields. This new one-pot protocol would be an ideal and rapid method to synthesize compounds in a combinatorial context.