A series of bis(gallyl) lanthanide(ii) complexes, [Ln(II){Ga[(ArNCH)(2)]}(2)(tmeda)(2)] (Ln = Sm, Eu or Yb; Ar = C(6)H(3)Pr(i)(2)-2,6), and a gallyl thulium(iii) compound, [Tm(III){Ga[(ArNCH)(2)]}{(ArNCH)(2)}(tmeda)], have been prepared; the first structural studies of Ga-Tm and Ga-Sm bonded complexes are described.