10-(Alkylamino)thieno[3,4-b][1,5]benzoxazepines (3) and 10-(alkylamino)thieno[3,4-b][1,5]benzothiazepines (4) were prepared by derivatization of the respective lactams (7 and 8) via phosphorus pentachloride and subsequent condensation with the appropriate alkylamines. 9-(Alkylamino)-4H-thieno[3,4-b][1,4]benzodiazepines (5) were prepared by titanium tetrachloride catalyzed condensation of the lactam 11 with alkylamines. 9-(Alkylamino)-4-methylthieno[3,4-b][1,4]benzodiazepines (6) were prepared by reductive alkylation of 5. The compounds were tested for potential neuroleptic activity by means of the blockade of d-amphetamine lethality in aggregated mice and/or effects on locomotor activity in rats. Antidepressant activity was examined using inhibition of tetrabenazine-induced depression in mice. Most of the title compounds 3-6 were found to have neuroleptic activity. In addition, introduction of a 3-chloro substituent in the oxygen and sulfur systems (3p and 4c), as well as introduction of an N-alkyl in the dinitrogen system (6), was found to produce antidepressant effects. Structure-activity relationships are discussed.