Heterocyclic compounds of the formula: ##STR1## wherein the pyrroline ring and the symbols X.sub.1 and X.sub.2 together form an unsubstituted or substituted isoindoline nucleus, or a 6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine, 6,7-dihydro-5H-pyrrolo[3,4-b]pyridine or 2,3,6,7-tetrahydro-5H-1,4-oxathiino[2,3-c]pyrrole nucleus, the 1,8-naphthyridin-2-yl nucleus is unsubstituted or substituted, and the grouping --NR.sub.1 R.sub.2 is an amino or substituted amino group, are new compounds which are active as tranquillizers, hypnotics, anti-convulsant agents and anti-spasmodics.