A series of polyethers consisting of a conjugated segment connected with a nonconjugated spacer were synthesized and characterized. On the basis of the chemical structure of the conjugated moiety, controllable light emission was obtained. The thermal properties were influenced from the structure of the conjugated segment, the type of substituents used, and the length of the flexible spacer used. Additionally, coil-rod-coil block copolymers having conjugated segments as the rod block were prepared with atom transfer radical polymerization of alpha,omega-modified conjugated oligomers. The optical properties of these copolymers were examined with respect to their aggregation behavior. (C) 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2485-2491, 2003.