I (CN) 2 ] 2 } (M = Mn, Co) were synthesized and characterized crystallographically and magnetically. The 2-D layer structure is composed by infinite cyano bridged Fe[Au(CN) 2 ] 2 . The layers are combined with another layer by strong aurophilic interactions defining bilayers. Compound of 100 % Fe ions undergoes a complete two-step spin transition with large hysteresis loop. Doped compounds shows the characteristic of gradual spin transition without hysteresis loop. The metal doping effect on spin transition properties are discussed.