Efficient energy transfer between a cationic poly(fluorene-co-phenylene) and thiazole orange mediated by a G-rich oligonucleotide provided sensitized TO emission over 25000-fold more intense than that from free TO. Higher energy transfer efficiency to ssDNA/TO relative to dsDNA/TO leads to an improved sensitivity and selectivity in G-rich DNA hybridization detection as compared to the direct use of TO as the signal reporter. The signal amplification provided by conjugated polymers is useful to amplify the response from other TO-based detection protocols.