3-(Thien-2-yl)-piperazin-2-ones, substituted in the 3-position, of the general formula ##STR1## wherein R dentoes, for example, phenyl or (C.sub.1 -C.sub.6)-alkyl and R.sup.1 denotes 2-thienyl and pharmacologically tolerable acid addition salts thereof, which possess valuable nootropic properties. The invention also includes methods for making such compounds, formulations containing such compounds and methods for treating a host in need thereof.