Abstract: An isonitrile ligand, 2 methyl cyclohexylisonitrile (MCHI) is synthesized and a copper salt (Cu(I)(MCHI) 4BF 4) of this ligand is also prepared. The isonitrile and its copper salt are characterized by IR and elemental analysis. The complex 99 Tc mN MCHI is prepared by ligand exchange reaction. The results of partition coefficient and stability studies indicate that the complex is lipophilic and stable over a period of 6 h at room temperature. Biodistribution of this new complex in mice show that it has certain uptake in myocardium and brain and retained there for a certain time. But also it is taken up in blood highly. Besides, the complex 99 Tc m MCHI is prepared and it has different characteristics with 99 Tc mN MCHI complex.