Abstract: The present invention generally relates to emissive materials, devices, and related methods. In some cases, the present invention provides sensors and methods for the determination of analytes, wherein the analytes may be determined by monitoring, for example, a change in an optical signal of an emissive material upon exposure to an analyte. The analyte and the emissive material may interact via a chemical reaction, such as an oxidative addition 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 useful in the detection of a wide variety of analytes, such as toxins, chemical warfare agents, and explosives. The present invention also provides emissive compounds, and related methods, including metal complexes that are capable of interacting with an analyte to produce a change in the emission of the compound.