The extraction efficiency of uranium(vi), thorium(iv), and lanthanum(iii) from nitric acid solutions to 1,2-dichloroethane was compared for a series of phosphoryl podands of the acidic type different in polyether chain length and number of oxygen atoms: 2-[(HO)(EtO)(O)P]–C6H4–(OCH2CH2)m–OC6H4–2-[P(O)(EtO)(OH)] (1–3, where m = 1–3) and 2-[(HO)(EtO)(O)P]–C6H4–O(CH2)5O–C6H4–2-[P(O)(EtO)(OH)] (4). The synthesis of podands 1 and 4 obtained for the first time is described. The molecular and crystal structures of podand 1 were determined by X-ray diffraction analysis, and the formation of a strong intramolecular hydrogen bond was observed. Podand 2 is the most efficient extractant for the selective recovery of ThIV in the presence of UVI and LaIII among the studied podands. Micellar aggregates 3–5, 6–90, 3–70, and 7–10 nm in size were found by the dynamic light scattering data in thorium extracts of podands 1–4, respectively.