Treatment of CoCl2 center dot 6H(2)O and tris(pyrazolyl-1-yl)borate tricyanoiron(III) anions at 55 degrees C afforded a series of new Fe-Co polynuclear clusters: {Co,Cl-2 (DMF)(4)[(Tp(4-Me)) Fe(CN)(3)](2)} (1; Tp(4-Me) = hydridotris(4-methylpyrazol-1-yl) borate), (H3O+)@{Co4Cl4 [(Tp(4-Me))Fe(CN)(3)](4)} (2), (MePh3P)(4){Co6Cl6[(Tp(4-Me))Fe(CN)(3)](6)}center dot 15CH(3)CN center dot 3CH(3)OH center dot 2H(2)O (3), and (BnEt3N)(4){Co5Cl8[(Tp*)Fe(CN)(3)](4)}center dot 4CH(3)CN center dot 2H(2)O (4; Tp*= hydridotris(3,5-dimethylpyrazol-1-yl)borate). They feature an asymmetric [Fe2Co2(CN)(4)] square, a pseudocubic [Fe4Co4(CN)(12)] cluster, a distorted-hexagonal-prism-shaped [Fe6Co6(CN)(18)] cage, and a bis(trigonal-bipyramidal) cluster of [Fe4Co5(CN)(12)] fused at one cobalt center, respectively. The Co(II) ions adopt a four-coordinate tetrahedral geometry except for half of 1 in an octahedral geometry. It should be mentioned that 3 and 4 provide two novel molecular skeletons in the cyanometalate family. Interestingly, 1 behaved as a single-molecule magnet with an effective energy barrier for spin reverse of 30.7 K at zero dc field. Our result demonstrated a possible self-assembly route toward high-nuclearity cyanide-bridged clusters by introducing four-coordinate cobalt(II) ions.