The effect of the 3-carboxylic-ester variation in 2, 2-dimethyltrimethylene 3-alkoxycarbonyl-4-aryl-1, 4-dihydro-2, 6-dimethyl-5-pyridinephosphonates (1) was investigated with relation to the calcium-antagonistic and antihypertensive activities : the analogs contaning the alkyl groups of not more than 12 carbons and an amino functionality in the carboxylic-ester moiety were synthesized to be examined for biological activities. Among them, 2-[benzyl(phenyl)amino]-ethyl 5(5, 5-dimethyl-2-oxo-1, 3, 2-dioxaphosphorinan-2-yl)-1, 4-dihydro-2, 6-dimethyl-4-(3-nitrophenyl)-3-phridine-carboxylate hydrochloride ethanol (NZ-105) showed particularly beneficial activities and was selected for further pharmacological studies and clinical development. Some aspects of the structure-activity relationships and solid-state structure of NZ-105 by X-ray crystallographic analysis were described.