The distal amino acid residues in myoglobin (Mb) and hemoglobin (Hb) are elaborately designed to control the chemical reactions of ligands to the heme iron. Many techniques have been applied to elucidate the reaction mechanism of ligand binding in heme pockets. Recently, vibrational circular dichroism (VCD) has emerged as a promising technique for investigating the coordination geometry of ligands bound to heme proteins.1 In the present study the time evolution of VCD band of azide ligand of reconstituted myoglobin was measured to obtain new insights into the stereochemical structure of coordination geometry of heme ligands and the VCD of a model system of a C2 chiral strapped iron porphyrin was studied for understanding the VCD origin of heme ligand vibration.