Atropisomeric energy-transfer dye compounds are disclosed. A variety of molecular biology applications utilize atropisomeric xanthene fluorescent dyes as labels for substrates such as nucleotides, nucleosides, polynucleotides, polypeptides and carbohydrates. Methods include DNA sequencing, DNA fragment analysis, PCR, SNP analysis, oligonucleotide ligation, amplification, minisequencing, and primer extension.