Nitrogen-containing heterocyclic compounds of the formula (I):
wherein Y is N or CH; R 1 , which may be optionally bound through a hetero atom, is a hydrocarbon residue which may be substituted; R 2 and R 3 which may be same or different, are each independently hydrogen, cyano, nitro, optionally substituted lower alkyl, or -COD wherein D is alkoxy, hydroxy, halogen, or optionally substituted amino; or R 2 and R 3 are taken together to form a benzene ring which may be substituted; the dotted line is a chemical bond; Z is bound to a hetero nitrogen atom and is a group having the formula:
wherein R 4 is hydrogen, halogen or nitro, and R 5 is a residue capable of forming an anion or a residue convertible into an anion; A is a direct bond or a spacer having atomic length of two or less between the phenylene group and the phenyl group; and n is an integer of 1 or 2; and the pharmaceutically acceptable salts thereof, have potent angiotensin II antagonist activity and antihypertensive activity, thus being useful as therapeutic agents for treating circulatory system diseases such as hypertensive diseases, heart diseases, strokes, etc.