2pz orbitals of ten carbon atoms of two C5H5¯ are involved in bonding with, nine cobalt orbitals. The coefficient of eigen vector of 2pz of carbon are in the range 0.70-1.88. The major involvements are in molecular orbitals 28- 54. The nine atomic orbitals which are involved in bonding are one 4s, there 4p and five d. The coefficients of eigen vector are in the range 1.50-4.42. The highest value is of 4s and lowest of 3dz2. The involvements of d orbitals are in MOs 23-31 and of 4s and 4p in the MOs 36-56. The MOs involving d orbitals have eigen values in the range -0.49 to -0.35 (e.V), that is in bonding range whereas 4s and 4p orbitals are in the range -0.08 to 2.04, which is anti bonding range. Energy levels diagram giving full quantitative details of involvement of atomic orbitals in molecular orbitals have been drawn population analysis showing extent of involvement of electrons is also presented.