A monosubstituted polyacetylene having amine functional groups was prepared via the polymerization of 3-ethynylaniline by using transition metal catalysts. The polymerization proceeded well in homogeneous manner to give a relatively high yield of polymer. The polymer structure was characterized by such instrumental methods as IR, NMR, and UV-visible spectroscopies to have the conjugated backbone system with the designed functional groups. The absorption spectrum starts around 700 nm, which is due to the pi -> pi* interband transition of conjugated polymer system. This polymer exhibited the irreversible electrochemical behaviors between the doping and undoping peaks.