Three novel coordination polymers built of octahedral niobium cyanochloride clusters [Nb6Cl12(CN)6] and alkaline earth metal complexes have been prepared by reaction of aqueous solutions of (Me4N)(4)Nb6Cl18 and KCN with solutions of alkaline earth metal salts and 1, 10-phenanthroline (phen) (1:2 molar ratio) in H2O/EtOH. The structures of [Ca(phen)(2)(H2O)(3)](2)[Nb6Cl12(CN)(6)]center dot(phen)(EtOH)(1.6) (1), [Ca(phen)(2)(H2O)(2)](2)[Nb6Cl12(CN)(6)]center dot(phen)(2)center dot 4H(2)O (2), and [Ba(phen)(2)(H2O)](2)[Nb6Cl12(CN)(6)] (3) were determined by single-crystal X-ray diffraction. The three compounds were found to crystallize in the monoclinic system (space group Pn) with a = 11.5499(6) angstrom, b = 17.5305(8) angstrom, c = 21.784(1) angstrom, beta = 100.877(1)degrees for 1; triclinic system (P1 ($) over bar) with a = 12.609(4) angstrom, b 13.262(4) angstrom, c = 16.645(5) angstrom, alpha = 69.933(6)degrees, alpha = 68.607(6)degrees, gamma = 63.522(5)degrees for 2; and a = 16.057(1) angstrom, b = 16.063(1) angstrom, c = 16.061 (1) angstrom, alpha = 86.830(1)degrees, beta = 64.380(1)degrees, gamma = 67.803(1)degrees for 3. Compounds 1 and 2 are built of cluster anions [Nb6Cl12(CN)(6)](4-) trans-coordinated by two Ca2+ Complexes via CN ligands to form neutral macromolecular units [Ca(phen)(2)(H2O)(3)](2)[Nb6Cl12(CN)(6)] in 1 and [Ca(phen)(2)(H2O)(2)](2)[Nb6Cl12(CN)(6)] in 2. Water of coordination and cyanide ligands form hydrogen bonded 3D and 2D frameworks for 1 and 2, respectively. The structure of 3 consists of [Nb6Cl12(CN)(6)](4-) cluster anions and [Ba(phen)(2)(H2O)](2+) complexes linked through bridging cyanide ligands to form a neutral three-dimensional framework in which each barium complex is bound to three neighboring Nb-6 clusters and each Nb-6 cluster is linked to six Ba complexes.