hydrogen or halogen y is hydrogen halogen cyano trifluoromethyl or alkyl containing 1 to 4 carbon atoms r is alkylidene or monosubstituted alkylidene containing 1 to 3 carbon atoms wherein the substituent is alkyl containing 1 to 4 carbon atoms and r 1 and r 2 are the same or different and represent hydrogen or alkyl containing 1 to 4 carbon atoms this invention also concerns substituted diphenyl ethers which in another embodiment are represented by the above formula wherein x y r r 1 and r 2 are as above defined but wherein z is halogen or cyano exemplary of halogens represented by the various substituents in the above formula are bromine chlorine iodine or fluorine preferably bromine or chlorine some alkyl groups suitable as substituents in the above formula are for example methyl ethyl n propyl isopropyl n butyl isobutyl and t butyl as alkylidene radicals there may be mentioned methylidene ethylidene and propylidene preferred compounds in accordance with this invention are those wherein x is hydrogen y is halogen e g chlorine and z is nitro 2 39 2 39 dimethyl 1 39 3 39 dioxolane 4 39 methyl 5 2 chloro 4 trifluoromethylphenoxy 2 nitrobenzoate is exemplary of a preferred compound of this invention compounds of the above formula are believed to have herbicidal activity in accordance with this invention those compounds wherein the z substituent is other than nitro e g halogen are believed to be somewhat more herbicidally active when applied postemergent rather than preemergent.