Unique effects of pi-conjugated polypyridine (PPy) blocks on fluorescence from the following macromolecular systems have been examined: (A) poly(2,2'-bipyridine-5,5'-diyl) (PBpy)-Ru(bpy)(2), (b) block-type copolymer of pyridine and selenophene, and (c) a system containing poly(6-hexylpyridine-2,5-diyl) (6HexPy) and poly(2-methylanthraquinone-1,4-diyl) (P2MeAQ). The PPy blocks in the systems serve as good molecular antennas and transfer the photoactivated energy to other molecular parts of the systems connected to the PPy blocks, thus causing emission of light from the other molecular parts.