A series of dialkyl p-substituted phenyl-and benzylphosphonates have been synthesized for the study of the relationship between structure and some physical and chemical properties. These compounds show various degrees of exaltation of refraction[∑E]，depending on the nature of nuclear substituents. It is a consequence of the conjugation effect resuiting from the intermolecular electronic interaction between the substituents and the benzene ring.By using acetylated paper and appropriate mobile phase, the title phosphonates can be separated chromatographically. The RF values of such compounds are closely related to the number of carbon atoms of the ester alkyl group. The method may be employed for separation and identification of other neutral phosphonates and probably also phosphate and phosphinates.