The development of new methods for sensing of toxic compounds in the environment is an important research area. Molecular sensors based on coordination complexes involve detection of small molecule analytes as ligands on transition metal complexes. In our approach, a hemilabile ligand is incorporated which remains tethered to the metal after the analyte binds, displacing the weakly bound end of the ligand. We utilize an emissive group tethered to the hemilabile ligand as a reporter group, and look for changes in the fluorescence response from the emitter. Using this approach, we have built a molecular sensor for carbon monoxide. Synthesis of new complexes, incorporation into thin-films and sol-gel glasses are new directions for this project.