1-Azinyl-tetraozolinones of the following formulae (I) and (II): ##STR1## wherein R.sup.1 and R.sup.2 are independently represent alkyl, haloalkyl, cycloalkyl, alkenyl, haloalkenyl, alkynyl or optionally substituted phenyl, or R.sup.1 and R.sup.2, together with the nitrogen atom to which they are bonded, may form a 5- or 6-membered heterocyclic ring which may optionally contain a further heteroatom, and said heterocyclic ring may optionally be benzo-condensed and/or be substituted by one or more of C.sub.1-4 alkyl(s), and R.sup.3 is a 6-membered heterocyclic aromatic group consisting of carbon atoms and 2 or 3 nitrogen atoms, which may optionally be substituted by halogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy, C.sub.1-4 alkylthio, di(C.sub.1-4 alkyl)amino or phenyl. The compounds of the formula (I) exhibit an excellent herbicidal activity and the compounds of the formula (II) are useful as starting materials in the production of the compounds of the formula (I).