A new series of 7-chloro- and 7-nitro-5-methoxy-5-phenyl-1,5-dihydro-2H-1,4-benzodiazepin-2-ones (7a, c--e) was synthesized and found to have potent antipentylenetetrazole activity. These compounds were also employed as intermediates in the synthesis of 3-substituted 1,3-dihydro-1,4-benzodiazepin-2-ones (8f--v).