We measured conducting and magnetic properties of (ET)(4)[Ln(NCS)(6)](CH2Cl2)-C-. (Ln = Dy, Ho, Er, and Yb), (ET)(5)[Ln(NCS)(6)NO3](EtOH)-Et-. (Ln = Tb and Dy), and (TTF)6[Dy(NCS)6]. All of the complexes behaved as semiconductors irrespective of Ln ions used, and also exhibited anomalous frequency-dependence of ac magnetic susceptibility below ca. 10 K, especially for Dy derivatives, indicating blocking behavior as found in single-molecule magnets.