Recent progress in organic chemistry increases the possibility of controlling metal ions/organic molecules interaction. The use of macrocycles or polypodands (1) makes possible the creation of specific extractants for each metal ion. According to the actual needs in pollution elimination and precious metal recovery, this approach can lead to important renewals of extractants used in hydrometallurgy. In the present work, selective extraction of plutonium by dicyclohexano-18-crown-6 (DCH18C6) and paladium by thiapolypodands from high-level nuclear waste solutions is investigated, and the results are modeled and discussed.