Certain interesting complexes of cycloheptaamylose and the ion-binding antibiotics beauvericin and prolinomycin have not yielded to solution by traditional methods of X-ray crystallography. These two independent classes of complexes have in common high molecular symmetry which has allowed successful solution of some of them by applications of the Rossman-Blow rotation function to locate noncrystallographic symmetry or to locate a known (or suspected) group within the crystal structure. This method will be used to solve more structures of the above classes with further investigation of the problems involved in its application to crystal structure determination.