Alkenylfluorosilanes, phenylfluorosilanes or alkynylsilanes smoothly dimerize in the presence of a copper(I) salt in a polar solvent such as N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) to give the 1,3-conjugated dienes, biphenyl or 1,3-conjugated diynes, respectively.