1,?3-?Bis(2-?chloroethyl)?benzimidazolin-?2-?one is an impurity of Filbanserin (F336750), an agonist of serotonin-5HT1A receptor and an antagonist of the 5-HT2A receptor. Binds dopamine receptors with Ki values ranging from 4-24 nM. Used to treat hypoactive sexual desire disorder in females.