Elucidation of the chemical basis of biological phenomena is often the least focused branch of science. However, understanding the chemistry of biological macromolecules in the 3-Dimension (3D) is an essential first step toward rational drug discovery. "Structural Chemistry" using the 3D structure, especially protein or nucleic acids, can reveal how they acquire their 3D structure and how dynamicity alters their biological function to show different chemo-biological behavior. Understanding the 3D structural system for the target macromolecules associated with particular disease by synergistic use of structural chemistry and biochemistry is especially important in this context. It has recently become possible to build a molecular model through in silico methods, which can complement the study of biological mechanisms (including the disease target) in the overall endeavor toward structure-based drug design. Thus