The present invention relates to a novel four-step process for the preparation of herbicidal and plant growth regulating 2-nitro-5-(2-pyridinyloxy)acetophenone oxime ether derivatives of formula I ##STR1## wherein R.sup.1 is hydrogen, cyano, halogen, nitro, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 haloalkyl,R.sup.2 is hydrogen or halogen,R.sup.3 is C.sub.1 -C.sub.4 alkyl andR.sup.4 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 cyanoalkyl, C.sub.3 -C.sub.5 alkenyl, C.sub.3 -C.sub.5 -haloalkenyl, C.sub.3 -C.sub.5 alkynyl, or C.sub.1 -C.sub.4 alkyl which is substituted by C.sub.1 -C.sub.4 alkoxy, halogen, C.sub.1 -C.sub.4 alkoxycarbonyl, C.sub.1 -C.sub.4 alkylaminocarbonyl or di(C.sub.1 -C.sub.4)alkylaminocarbonyl,which process comprises converting a phenol of formula II ##STR2## by reaction with a compound of formulaH.sub.2 N--O--R.sup.4 (III)into an oxime ether of formula IV ##STR3## in the presence of a base; reacting said oxime ether with a 2-halopyridine of formula V ##STR4## wherein Hal is chlorine or bromine, in the presence of an acid acceptor; and nitrating the resultant oxime ether of formula VI ##STR5## with a nitrating agent.