In this paper the dielectric properties of a large group of solid and liquid organic substances are discussed theoretically from the point of view of modem atomic and molecular structure. It is shown that in such substances dipoles have two equilibrium positions with opposite dipole direction. The static dielectric constant should increase with temperature below a critical temperature and decrease above it. The power loss for crystalline solids should be approximately described by the Debye equations. For amorphous substances, however, a flattening-out of the Debye loss curve is expected. For long chain molecules the dependence of the time of relaxation on chain length has been calculated.