Novel pyrazolo[4,3-c]cinnolin-3-one derivatives of the formula ##STR1## wherein R may be in the 7- or 8-position and is selected from the group consisting of hydrogen, halogen, alkyl and alkoxy of 1 to 5 carbon atoms, --NO.sub.2 and --CF.sub.3 and R' is hydrogen or R and R' taken together form an alkylenedioxy of 1 to 4 carbon atoms at the 7- or 8-positions and R.sub.1 is selected from the group consisting of phenyl, pyridyl, thiazolyl, dihydrothiazolyl and thienyl, all optionally substituted with at least one member of the group consisting of alkyl and alkoxy of 1 to 5 carbon atoms, halogen, mono-, di- and tri- halomethyl and aralkoxy of 7 to 12 carbon atoms and their non-toxic, pharmaceutically acceptable acid addition salts having anxiolytic properties and novel intermediates therefore.