Abstract The two azacages 1–2,4-dinitrobenzene-7,13-dimethyl-1,4,7,10,13-pentaazabicyclo[5.5.5]eptadecane (1) and 1–2,4-dinitroben-zene-1-2,4-dinitrobenzene-8,14-dimethyl-1,5,8,11,14-pentaazabicyclo [7.5.5]nonadecane (2) have been synthesized by two different synthetic routes. The basicity behavior in mixed water/DMSO solution has been studied by potentiometry (25 °C, I = 0.10 mol dm−3): logK1 = 12.76(8), logK2 = 3.84(5) for (1). The low solubility of (2) prevents the accurate basicity constants determination. Crystals of (2) are monoclinic, space group P21/a, with a = 11.944(3), b = 13.587(6), c = 15.034(4) A, β = 90.36(2)° and Z = 4; final R = 0.059 (wR2 = 0.1632) for 1211 unique observed reflections with I > 2σ(I). Both cages are able to encapsulate Li+ ion, the 7Li NMR spectra (CD3OD) of [Li(1)]+ and [Li(2)]+ show sharp signals at 3.52 and 2.50 ppm respectively and indicative of high deshielded cation.