The crystal and molecular structures of (A) 3,5-Diacetyl-2,6-dimethyl-4-(3'-nitrophenyl)-1,4-dihydropyridine, (B) 3,5-Dibenzoyl-2,6-dimethyl-4-(3'-nitrophenyl)-1,4-di hydropyridine and (C) 3,5-Dicarbomethoxy-2,6-dimethyl-4-(4'-methylthiophenyl)-1,4-dihydropyridine derivatives were determined by X-ray diffraction methods. The compound (A), C17H18N2O4 crystallises in the monoclinic space group P2(1)/n with a = 7.537(3) Angstrom, b = 16.273(3) Angstrom, c = 12.474(4) Angstrom. beta = 92.60(3)degrees, V = 1528.4(8) Angstrom(3), Z = 4, D-calc = 1.3661 Mg/m(3), mu = 0.812 mm(-1), F-000 = 664, CuK alpha = 1.5406 Angstrom and R = 0.0956. The compound (B), C27H22N2O4, crystallises in the monoclinic space group P2(1)/c with a = 7.3113(7) Angstrom, b = 23.3925(7) Angstrom, c = 13.0737(7) Angstrom, beta = 91.31(7)degrees, V = 2235(3) Angstrom(3), Z = 4, D-calc = 1.303 Mg/m(3), mu = 0.176 mm(-1), F-000 = 920, CuK alpha = 1.5406 Angstrom and R = 0.0768. The compound (C), C18H21NO4S crystallises in the orthorhombic space group Pnca with a = 13.205(3) Angstrom, b = 26.558(3) Angstrom, c = 10.244(3) Angstrom, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, V = 3592.6(12) Angstrom(3), Z = 8, D-calc = 1.521 Mg/m(3), mu = 2.050 mm(-1), F-000 = 1728, CuK alpha = 1.5406 Angstrom and R = 0.0535.