Low-temperature magnets derived from Fe[N(CN)(2)](2)(pyrimidine) have guest molecules incorporated in the clearance of the 3-D framework. The ac and dc magnetic susceptibility measurements reveal that the temperature of magnetic phase transition (T-N) depends on the guest molecules. They are characterized as weak ferromagnets below T-N. The compound containing uncoordinated pyrimidine molecules as a guest showed the highest T-N of 5.6 K in this family.