A straightforward, novel, and extremely rapid method is developed for the synthesis of polythioether based on the reaction of dimethyl acetylenedicarboxylate with electron-deficient triple bond and 1,6-hexanedithiol in CHCl3 using an organobase 1,5,7-triazabicyclo[4.4.0]dec-5-ene at room temperature. The influence of various parameters, such as concentration of monomers, solvent, catalyst, and reaction time, on the polymerization was investigated through kinetic studies. Polythioether with molecular weight up to 60 kDa was quantitatively achieved in 1 min, under the optimum experimental conditions. Various dithiol compounds were then reacted with dimethyl acetylenedicarboxylate to enhance polymer diversity. Following, three propiolate compounds were reacted with 1,6-hexanedithiol to explore their ability for polythioether synthesis, but low to moderate molecular weights were achieved compared to those with dimethyl acetylenedicarboxylate. The versatility of these polythioethers was shown by postpolymerization functionalization studies. Considering the huge demand for rapid polymerizations in high efficiency under mild reaction conditions, the current study will offer remarkable opportunities toward the design of new polymeric materials.