Zirconium and hafnium are two of the most important nuclear materials. The use of zircaloy in the construction of fuel elements and other structural components in reactor cores meets many physical and technological requirements. Zirconium metal should contain less than 100 ppm hafnium for use in nuclear reactors. It is well known,zirconium and hafnium have very similar chemical properties and are commonly referred to as “chemical isotopes”. In recent years, the problem of separation of zirconium and hafnium has acquired significant importance. The main objective of the present investigation is to design and develop new liquid-liquid extraction systems based on novel heterocyclic ?-diketonates in the presence and absence of various neutral organophosphorus extractants or macrocyclic crown ethers, with a view to improve both the extraction efficiency and selectivity between Zr(IV) and Hf(IV). The secondary objective of the present study is to generate knowledge base, especially, to understand the interactions of neutral organophosphorus extractants or crown ethers with heterocyclic ?-diketonate complexes of Zr(IV) and Hf(IV) to achieve better selectivity.