The present invention provides sensors and methods for determination of an analyte. The analytes may be determined by monitoring, for example, a change in an optical signal of an emissive material upon exposure to an analyte. In some embodiments, the analyte and the emissive material may interact via a chemical reaction, or other chemical, biochemical or biological interaction (e.g., recognition), to form a new emissive species. In some cases, the present invention may be used for the detection of analytes such as explosives (e.g., RDX, PETN). Methods of the present invention may be advantageous in that the high sensitivity of luminescence (e.g., fluorescence) spectroscopy can allow for the reliable detection of small changes in luminescence intensity.