Diphenylalkanoether and diphenylalkanone oximeether derivatives of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are each independently an aryl group optionally substituted with 1 to 3 substituents selected from the group consisting of halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro, cyano, di(C.sub.1 -C.sub.4)alkylamino, amino, benzyloxy, hydroxyl, C.sub.1 -C.sub.4 alkylthio, C.sub.1 -C.sub.4 alkylsulfinyl, C.sub.1 -C.sub.4 alkysulfonyl, C.sub.1 -C.sub.4 alkanoylamino, C.sub.1 -C.sub.4 alkylmino and N-(C.sub.1 -C.sub.4)alkyl-N-(C.sub.1 -C.sub.4)alkanoylamino, Z.sup.1 is a group of the formula: ##STR2## (wherein R.sup.3 and R.sup.4 are each independently a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group or an ar(C.sub.1 -C.sub.4)alkyl group or, when taken together with the adjacent nitrogen atom to which they are attached, represent a nitrogen-containing 5 to 7-membered saturated heterocyclic group optionally having an oxygen atom or an additional nitrogen atom as the hetero atom in additon to the said nitrogen atom and, in case of having the additional nitrogen atom, bearing a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, an ar(C.sub.1 -C.sub.4)alkyl group or a phenyl group thereon), ##STR3## is a group of the formula: ##STR4## or the formula: ##STR5## A.sup.1 is a C.sub.2 -C.sub.6 alkylene group and A.sup.2 is a C.sub.2 -C.sub.4 alkylene group, and non-toxic, pharmaceutically acceptable acid addition salts thereof, which have cerebral vasodilating activity and antihypoxic activity.