The dissociative photoionization channels of gaseous Si(CH3)Cl-3 and ion desorption mechanisms of solid-state analogs following valence-level excitation have been investigated by means of photoionization mass spectroscopy, threshold photoelectron spectroscopy (TPES), and photon-stimulated ion desorption (PSID) using synchroton radiation. The adiabatic ionization threshold of the parent molecular ion was determined to be 11.18 eV, consistent with the value of 11.16 eV obtained from the TPES spectrum. An energy shift similar to 0.8 eV toward lower binding energies for the orbitals of solid Si(CH3)Cl-3 with respect to the gas phase values was observed. Two thresholds at 14.97 and 17.51 eV in the CH3+ photoionization efficiency spectrum are probably associated with the ionization of 2e " and 11a(1) orbitals, respectively. The H+ desorption threshold at 20.1 eV in the PSID spectrum may be attributed to the excitation of C 2s electron correlation states to the unoccupied states. The Cl+ desorption threshold at 19.9 eV is likely initiated by an Auger-stimulated desorption process.