We present a unique interpretation of X-ray absorption spectroscopy (XAS) spectra at Cu:K, W:L 3 , and Mo:K edges of structurally related magnetic Cu II − [M V (CN) 8 ] 3 − compounds. The approach results in description of the structure of novel three-dimensional (3-D) Cu II 3 (pyz)- [M V (CN) 8 ] 2 · x H 2 O, M = W ( 1 ), Mo, ( 2 ) polymers. Assemblies 1 and 2 represent hybrid inorganic − organic compounds built of {Cu II [W V (CN) 8 ] − } n double-layers linked by cyanido-bridged {Cu II − ( μ -pyz) 2+ } n chains. These Cu II − M V systems reveal long- range magnetic ordering with T c of 43 and 37 K for 1 and 2 , respectively. The presence of the 3-D coordination networks and 8 cyanido-bridges at M V centers leads to the highest Curie temperatures and widest hysteresis loops among Cu II − [M V (CN) 8 ] 3 − systems.