Method for producing a bis-benzoxazole

The invention provides a o- aminophenol, after the carboxyl group to give the ammonium salt is reacted with a dicarboxylic acid are bonded to each other through a double bond or a conjugated double bond system, this ammonium salt, According to be converted to benzoxazole by microwave irradiation in the presence of a dehydration catalyst and a low dielectric loss solvent, a method for producing a bisbenzoxazole be linked to each other through a conjugated double bond system.