A highly efficient chemoselective synthesis of multifunctionalized tetrahydro-1H-pyrrolo[1,2-c]imidazole and tetrahydropyrrolo[1,2-c]thiazole derivatives has been established from arylglyoxal monohydrates, nitriles, and thioureas. A series of control experiments suggested that this reaction proceeded through the convergent integration of two self-sorting domino sequences. This synthetic strategy is promising for diversity-oriented synthesis of alkaloid analogues.