Complexes of lanthanides with N,N′-bis(2-hydroxybenzylidene)-2- hydroxyphenylmethanediamine (H₃L) were synthesized and investigated by the elemental, IR, magnetochemical, and thermogravimetric methods. Using the data obtained, they were found to have compositions Ln₂L ₂·nH₂O and La₂L₂· MCl₂·4H₂O (Ln = La³⁺, Pr³⁺, Nd³⁺, Dy³⁺, Er³⁺; M = Cu²⁺, Co ²⁺, Ni²⁺; n = 4, 6). Suggestions on their structures were made. In the interval of 20-140°C, these complexes were shown to be high-resistance semiconductors.