1,4-Dihydropyridines bearing carbonyl functions in the 3- and 5-positions, being optionally substituted by lower alkyl in the 6-position, being substituted in the 4-position by lower alkyl, phenyl, substituted phenyl or a heterocyclic group, and being fused through the 1- and 2-positions to a five, six or seven membered cycloalkyl ring, one methylene group of which can be replaced by sulfur, oxygen imino or alkylimino, are antihypertensive agents and coronary vessel dilators. The compounds, of which 6-methyl-4-(3-nitrophenyl)-1,2-pentamethylene-1,4-dihydropyridine-3,5-dicarboxylic acid 3,5-diethyl ester is a representative embodiment, are prepared through condensation of an ylideneacetoacetic acid ester and a cyclic enamino carbonyl derivative.