Circularly Polarised Luminescence (CPL) spectroscopy detects the differential emission of left and right circularly polarised light from luminescent chiral species, and so can be thought of as the emission analogue of circular dichroism spectroscopy. The circularly polarised emission of chiral europium complexes derived from the 12-ane-4 macrocycle cyclen, (examples of which are shown below) have been recorded using this technique. (Fig. 10701) These and similar complexes have shown an ability to bind to biologically important anions such as carbonate and phosphate in aqueous media and are able to report this event by a change in luminescence. These interactions have been investigated by monitoring the emitted circularly polarised light using the technique described and the binding of the substrate is clearly signalled. Typical CPL spectra of the europium complexes will be presented as will the binding study results and a detailed account of how the spectra is obtained.