efficient synthesis of a widerange absorbing azaphthalocyanine dark quencher and its application to duallabeled oligonucleotide probes for quantitative realtime polymerase chain reactions unsymmetrical dialkylaminosubstituted zinc azaphthalocyanine azapc exhibits unique spectral and photophysical properties for dark quenchers of fluorescence in dna hybridization probes the panchromatic light absorption of azapc from 300 nm up to at least 700 nm and its lack of fluorescence make it an ideal candidate for a universal dark quencher to prove this experimentally oligodeoxyribonucleotide probes were labeled at the 3end by this azapc and at the 5end by a fluorophore used in the polymerase chain reaction pcrthat is fluorescein cal fluor red 610 and cy5 azapc showed a significantly higher quenching efficiency compared to the commercially available dark quenchers bhq1 bhq2 bbq650 in a developed model of taqman pcr assay the azapclabeled probe proved to also be useful in a practical pcr assay for the quantification of the slco2b1 transporter gene expression the constructed calibration curves indicated linearity in the range from 102 to 107 of target copies