Abstract: An isonitrile ligand 3,3,5 trimethyl cyclohexylisonitrile(TMCHI) is synthesized and a copper salt (Cu(I)(TMCHI) 4BF 4) of this ligand is also prepared, the isonitrile and it's copper salt are characterized by IR and elemental analysis. The complex 99 Tc mN TMCHI is prepared by ligand exchange reaction and 99 Tc m TMCHI is prepared by 99 Tc m labelling directily with SnCl 2·2H 2O as reducing agent. The radiochemical purity of the two complexes are more than 95%. The results of stability study indicate that the two complexes are stable over a period of 6 h at room temperature. Biodistribution of the two complexes in mice indicate that they have a certain extent uptakes in myocardium and brain and retain in them for a certain time, but also they are mainly accumulated in blood and maintain in it very good. The T/NT ratios of the two complexes in mice are excellent as cardiac blood pool imaging agents. Based on these promising properties, they maybe suitable for cardiac blood pool imaging and the studies about it will be go on.