Substituted 1,2-diphenylaziridines, particularly those which are substituted by halogen, are useful as pesticidal compositions. These 1,2-diphenylaziridines are of the following formula: ##STR1## wherein X is selected from the group consisting of hydrogen, halogen, and nitro, and Y is selected from the group consisting of hydrogen, halogen, nitro, trifluoromethyl, and lower alkyl of 1-3 carbon atoms, and n is an integer of 1 or 2, provided that when one of X and Y is hydrogen or nitro, the other is halogen.
