Spectroscopic, solvent extraction methods and computational chemistry are applied for the characterization of redox sensitive trivalent plutonium complexed with the N-donor extracting agent alkylated 2,6-ditriazinylpyridines (n-C3H7-BTP) in organic solution. The redox stabilization and speciation of Pu(III) is discussed. Extraction of Pu(III) with n-C3H7-BTP is compared to that for redox stable Am(III). The speciation of Pu(III) with n-C3H7-BTP in organic solution is studied by UV-Vis/NIR and XAFS spectroscopy. Only the 1:3 complex, [Pu(n-C3H7-BTP)3](3+) is observed to form, which is confirmed by EXAFS and solvent extraction. The [Pu(n-C3H7-BTP)3](3+) complex is compared to the isostructural U(III), Am(III), and Cm(III) complexes studied earlier.