A compound of the general formula ##STR1## wherein R.sub.0 represents an alkyl group optionally having a substituent selected from the class consisting of a cyano group, lower alkoxy groups and di-(lower alkyl)amino groups, a lower alkenyl group, or a lower alkynyl group; R.sub.1, R.sub.2 and R.sub.3, independently from each other, represent a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group; R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8, independently from each other, represent a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group; Y represents a group of the formula ##STR2## or a group of the formula ##STR3## in which one of R.sub.9 and R.sub.10 is a lower alkyl group and the other is a hydrogen atom or a lower alkyl group; with the proviso that when Y is the group ##STR4## and R.sub.0 represents an unsubstituted alkyl group, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8 do not represent hydrogen atoms at the same time. The compounds of formula (I) are produced by the reaction of the corresponding benzenesulfonamide derivatives with the corresponding benzyl or benzoyl halides; the reaction of the corresponding benzenesulfonyl halides with the corresponding benzylamines or benzoyl amides; or by the alkylation, alkenylation or alkynylation of the corresponding compounds of formula (I) in which R.sub.0 is hydrogen. The compounds of formula (I) have superior selective herbicidal effects, and are useful as active ingredients of herbicides, especially those for application to aquatic rice paddies.