The elementary steps of an electron photodetachment triggered by the UV excitation of pure liquid dimethyl sulfide, (CH3)(2)S, have been investigated by femtosecond absorption UV-IR spectroscopy at 294 K. The buildup of a long-lived UV band centered around 420 nm (3.26 eV) is observed at the sub-picosecond time scale. This spectral band is assigned to a radical anion (CH3S therefore SCH3-) characterized by a sulfur-sulfur bond with an antibonded third electron (2c, 3e). A very short-lived electronic state, whose rise time equals 180 +/- 10 fs, exhibits a spectral overlap with this UV radical. The frequency and time dependences of induced absorption signals are analyzed in the framework of a kinetic model for which an early electron transfer yields an ultrashort-lived anion radical ({RSR-}(RSR) or {RSR [GRAPHICS] RSR}, R = CH3). The decay rate of this UV state (1/tau = 3.7 x 10(12) s(-1)) is rationalized by postulating an ultrafast ion-molecule reaction and the picosecond formation of a disulfide radical anion (CH3S therefore SCH3-) characterized by a 2 sigma/1 sigma* bond. A second electron-transfer channel leading to a delayed formation of a disulfide anion radical (RS therefore SR-) has been identified by time-resolved IR spectroscopy. These femtosecond investigations argue for an ultrafast formation of a sulfur-sulfur bond with C-S bonds breaking. It is suggested that the density-state fluctuations of organic sulfur molecules influence the energy of early electron-thioether couplings (electron attachment or localization) and would govern competitive branchings between ultrafast electron photodetachment channels.