||Recently, fluorescent conjugated polymers are being extensively investigated for their potential applications in the fields of optoelectronics, microelectronics, and chemical and biological sensors. Water-soluble conjugated polymers are interested towards the applications in biosensor materials because of their detection ability toward DNA and proteins. The detection of biological analytes can be achieved in high sensitivity using conjugated polymers based biosensory materials due to their large signal amplification even more trace amount of analytes. However, the conjugated polymers are not easy to dissolve in aqueous media because they are a hydrophobic in nature with rigid main chain. We synthesized a novel water-soluble poly(para-phenylene) copolymer containing charged sulfonate side chain groups and 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (TBT) units. The polymers are exhibited a visually noticeable blue-to-red fluorescence change by aggregation.