Herbicidal 1-alkenyltetrazolinones of the formula: ##STR1## wherein R.sup.1 represents the group: ##STR2## or the group: ##STR3## R.sup.2 and R.sup.3, independently of one another, represent C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl which may optionally be substited by methyl, C.sub.2-4 alkenyl, C.sub.2-5 alkynyl, phenyl which may optionally be substituted or aralkyl which may optionally be substituted, orR.sup.2 and R.sup.3 may optionally form, together with the N-atom to which they are bonded, a heterocyclic ring which may optionally be substituted, and novel intermediates therefor.