Most organic reactions have long been carried out in organic solvents without concern for their real necessity, reaction efficiency, and pollution problems. Very recently, we have found that most organic reactions can be carried out in the absence of a solvent, namely, in the solid state. In many cases, the solid-state reaction proceeds more easily and efficiently, and even more selectively than solution reaction. This shows that molecules move easily and selectively in the solid state. This finding changed the classical idea which suggests "molecules do not move and reactions do not occur...