A novel type of pi-extended 1,10-phenanthroline, specifically with fused thiophene groups at the less exploited 3-, 4-, 7-, and 8 positions of the phenanthroline ring, and its conjugated polymers were designed and synthesized. The current developed route is based on the Bischler-Napieralski cyclization of the (1,2-phenylene)diamide precursor, which offers a facile and versatile strategy for preparing soluble and well-defined 1,10-phenanthroline derivatives and their analogues. High molecular weight poly(phenanthroline-co-fluorene)s with good solubility in common organic solvents or water were prepared by palladium catalyzed Suzuki-Miyaura-Schliiter polycondensation. The optical responsive properties of these thiophene-fused 1,10-phenanthroline-containing polymers have demonstrated these polymers could be a good candidate for potential applications as luminescent chemosensor materials thanks to the specific repeating unit along the backbone.