Kinetically stabilized silaneselone [Tbt(Dip)Si=Se (4); Tbt=2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Dip=2,6-diisopropylphenyl] and silanetellone [Tbt(Dip)Si=Te] were synthesized by direct chalcogenation of Tht(Dip)M: (M=Si, Ge) with elemental chalcogen. Deselenation of Tbt(Dip)SiSe2 also gave 4. Metallanetellones [Tbt(Dip)M=Te; M=Si, Ge] were also synthesized by the reaction of Tbt(Dip)MLi2 (M=Si, Ge) with TeCl2, which is a new synthetic method for heavy ketones.