We report the observation of the CH3S(O)CH- and CH3S(O)CH-center dot H2O carbene anions formed upon overall H-2(+) abstraction from dimethyl sulfoxide by O-. Photoelectron spectroscopy reveals singlet and triplet carbenes for the remaining neutral, with the singlet state assigned as the ground state. Although some formation of the distonic CH2S(O)CH2-radical anion is also expected, no conclusive evidence of the presence of this isomer is found. The photoelectron spectrum of HCSO- is also reported for the first time. Photofragmentation of CH3S(O)CH- with 532 nm light reveals two main types of anionic products: a dominant HCSO-fragment, resulting from methyl elimination, and a less intense SO-product. For the monohydrated anion, an additional SO-center dot H2O fragment is observed. Intriguingly, both the SO-center dot H2O and SO-products are produced with much higher yields in the fragmentation of CH3S(O)CH-center dot H2O, compared to the SO- yield from the dissociation of the bare CH3S(O)CH- anion. Two possible pathways are proposed as likely mechanisms for the SO--based photoproducts, both involving a photoinduced intramolecular rearrangement and the formation of a C-C bond.