The incorporation of guanidinium ions (Hgua+) in Cu(II)–M(V) systems results in the formation of two isostructural coordination polymers (Hgua)Cu(II)[M(V)(CN)8], M = W (1); Mo (2), which reveal a double-layered structure separated by guanidinium ions. The magnetic measurements reveal long range magnetic ordering with critical temperatures of 32.8 and 27.5 K for 1 and 2, respectively. Moreover, both assemblies exhibit hysteresis loops with coercive fields of 300 Oe for 1 and 50 Oe for 2, and a spin-flip transition around 120 Oe.