The trichlorosilylcarbene monoradical (Cy-cAAC .)SiCl3 (1) was directly converted to (Cy-cAAC .)SiPh3 (2) by substitution of the three chlorine atoms with phenyl groups without affecting the radical center adjacent to the silicon atom. In addition to the structure determination, compound 2 was studied by EPR spectroscopy and DFT calculations. The three hyperfine lines in the EPR spectrum of 2 are due to the coupling with 14N nucleus. Functionalized 1,4-quinodimethane Me2-cAAC= C6H4=CPh2 (7) was isolated, whereas carbon analogue of radical 2 was targeted. Cyclic voltammogram of 7 indicated that a stable radical-anion 7 .-, as well as a radical-cation 7 .+, can be prepared. Theoretical calculations showed that one-electron ionization energy and electron affinity of 7 are 5.1 and 0.7 eV mol-1, respectively. Stable guys: A triphenylsilylcarbene radical, which was synthesized by substituting all the chlorine atoms of the silicon center by phenyl groups, was characterized and studied by EPR spectroscopy and DFT calculations. The synthesis of a carbon analogue of this radical was attempted. However, a carbene-functionalized conjugated 1,4-quinodimethane derivative was isolated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.