a, a’-Bis(substituted benzylidene)cycloalkanones were efficiently prepared from cycloalkanones and benzaldehydes in [bmim][BF4] by using iron(III) chloride hexahydrate as a catalyst. It is shown that [bmim][BF4] and iron(III) chloride hexahydrate can be quantitatively recovered and be reused effectively for many times. Compared with the known methods, this novel process has the advantage of being an envkonmentally benign process together with good yields and mild reaction conditions. It was shown that [bmim] [BF4] and iron (a) a’-Bis (substituted benzylidene) cycloalkanones were efficiently prepared from cycloalkanones and benzaldehydes in [bmim] [BF4] by using iron (III) chloride hexahydrate as a catalyst. Compared with the known methods, this novel process has the advantage of being an envkonmentally benign process together with good yields and mild reaction conditions.