Scorpions consist of a specific DNA probe sequence held in a hairpin loop with a particular three-dimensional arrangement (1)(2). Scorpion probes were modified to carry the components of an exciplex to allow their use in a new fluorescence-based method for specific detection of DNA sequences (3). The model of Scorpion-probe systems in this study consisted of a Scorpion target bearing one exciplex partner on the 5’-phosphate site, and the second oligonucleotide probe bearing the other exciplex partner on its 3’-phosphate site. The exciplex partners chosen (5’-pyrenyl and 3’-naphthalenyl) were attached to the oligonucleotide via a phosphoramidate link to the terminal phosphate groups (Fig. 1). Hybridisation led to adjacent binding of the 5’-Scorpion-pyrenyl and exci-probe-3’-naphthalenyl exciplex partners registered as an obvious spectral change on excitation from blue (pyrene locally excited state) fluorescence emission (λmax = 378, 397 nm) to green, exciplex emission (λmax = 466 nm) in 10 mM Tris, 0.1 M NaCl, pH 8.4 buffer containing 32% (v/v) TFE at 5 °C. TFE was sequentially added (19.6 %, 32 % and 41 %, v/v) and emission spectra taken after each addition. This addition gave rise to an increase in intensity at 466 nm for the all concentrations, and was largest for 32 % TFE (Fig. 2). This increase in fluorescence intensity can be attributed to exciplex formation by the pyrene-naphthalene exciplex. The shape (broad) and position (466 nm) of the band is typical of pyrene-naphthalene exciplex emission (3); the intensities of the monomer (LES) bands were quenched and the 466 nm band concomitantly increased in intensity. When the oligonucleotide probe bearing the naphthalenyl group was replaced by an identical one but with no naphthalenyl group on its 3’-phosphate site, no exciplex band was detected at 466 nm (Fig. 2). This indicates that the second exciplex partner is needed for exciplex emission at 466nm. This supports the observation that the emission detected in this study results from interaction between the exciplex partners, and the interpretation that the exciplex signals detected in the full systems of this study occur from correct hybridisation of the probe oligonucleotide on the Scorpion target strand and interaction of the exci-partners, rather than pyrene or naphthalene interacting with the nucleotide bases. These results show that it is possible to use Scorpion exciplex probes for detection of oligonucleotides sequences, with potential for future applications in genetic testing and molecular diagnostics.