The subpicosecond ultraviolet observation of a sulfur-sulfur bond making (2sigma/1sigma* bond) is carried out in pure liquid dimethyl sulfide at 294 K. The early stages of a disulfide bonded radical formation (CH(3)SthereforeSCH(3)(-)) are characterized by a nonlinear lambda(max) red shift of the absorption spectrum. In the temporal range 0-1600 fs, the red shift of 0.31 +/- 0.1 eV is analyzed in the framework of a change of the 2sigma/1sigma* transition due to a lowering of the 2c,3e S-S bond strength and/or a destabilization of the sigma lone pair during the demethylation process.