A convenient method of synthesis of bis-indolylmethanes: Indium trichloride catalyzed reactions of indole with aldehydes and Schiff's bases.

Anhydrous indium trichloride (InCl3) is found to catalyze the electrophilic substitution reaction of indole with aromatic aldehydes and Schiffs bases which resulted in an efficient synthesis of bis-indolylmethanes in good to excellent yield.