Low molecular weight, n 1800–2400, and soluble copolymers of acetylene and butadiene were prepared by nickel naphthenate–diethylaluminum chloride catalyst. These copolymers possess high cure tendency to give insoluble and highly crosslinked films. The curing ability can be controlled by the amount of acetylene content in the copolymer and is in the following order: acetylene–butadiene copolymer > tung oil > cis-1,4-polybutadiene ≫ linseed oil, 1,2-polybutadiene, butadiene–isobutylene copolymer. Chemical modifications of the copolymer such as maleic reaction, metallation by lithium or sodium, graft polymerization by methyl methacrylate, 4-vinylpyridine or vinyl acetate, and epoxidation were also examined. The divinyl methylene in the copolymer gives a high cure tendency and high chemical reactivity.