The single molecule magnet behavior of metal complexes containing a single magnetic ion was first reported for phthalocyaninatolanthanide complexes with a "double-decker" structure. In this paper, recent attempts by the author and coworkers at revealing the magnetism and electronic structures of the mononuclear and dinuclear lanthanide complexes with phthalocyaninato ligands are reviewed. (c) 2006 Elsevier Ltd. All rights reserved.