Pyrazoline compounds of the formula (I): ##STR1## in which each of B.sup.1 or B.sup.5 is hydrogen or C.sub.1 to C.sub.4 alkyl;R.sup.1 is hydrogen, alkyl or hydroxy;R.sup.2, R.sup.3, R.sup.5, R.sup.6 and R.sup.7 independently of one another are hydrogen, chloro, bromo, fluoro, methyl, ethyl, methoxy or ethoxy;R.sup.4 is hydrogen, alkyl, benzyl, phenylethyl or also phenyl optionally bearing chloro, bromo, methyl, ethyl, methoxy, ethoxy, cyano, dialkylamino or SO.sub.3 H as a substituent;X is --O--, --S--, --NR.sup.8 --, --NR.sup.8 CO--, --NR.sup.8 --SO.sub.2 --, --OSO.sub.3 -- or --SO.sub.3 --;R.sup.8 is hydrogen, alkyl or alkyl bearing hydroxy or C.sub.1 to C.sub.4 alkoxy as a sbustituent;A is hydrogen, sodium, potassium, unsubstituted or substituted ammonium, unsubstituted or substituted alkyl, cycloalkyl, aralkyl or aryl; and--NR.sup.8 -- and A together may be an optionally quaternized saturated or unsaturated heterocyclic ring.The compounds are eminently suitable as optical brighteners for example for acrylonitrile polymers, wool and polyamides.