Five 1,8-naphthalenediyl transition metal compounds 2 were prepared by treating either 1,8-naphthalenediylmagnesium (1) or 1,8-dilithionaphthalene with the appropriate transition metal dichloride LnMCl2: LnM = Cp2Ti (2a), (PEt3)2Pt (2b), Cp* PPh3Rh (2c), Cp* PPh3Ir (2d), or Cp*2Zr (2e). The resulting metallacycles were characterized by NMR and mass spectrometry. X-ray crystal structure analyses were performed for (1,8-naphthalenediyl)titanocene (2a) and (1,8-naphthalenediyl)bis(triethylphosphane)platinum (2b). Despite the strain induced by the four-membered metal-containing rings, the naphthalene units show remarkably small distortions.