The first two sections of this work discuss the development of a sensor system for metal ions. The same receptor, 2,2'-bipyridine, was used in all of the systems explored, and the overall specificity of the sensing system was achieved through binding equilibria and relative quenching rates. The first system discussed is a tetra-bipyridylphenyl-porphyrin. In all cases quenching results following formation of a ground state complex between a bipyridyl moiety of the porphyrin and the metal ion. For the Zn(II) tetra-bipyridylphenyl-porphyrin, luminescence quenching is only observed with Co(Il), Ni(II), and Cu(II). For luminescent species having multiple, independent, metal ion binding sites, detailed examination of the luminescence quenching clearly shows that association equilibria for binding metal ions at least two of the available sites must be taken into account In the second section, the results of varying the chromophore (from metalloporphyrin to Ru(bpy)3), the spacer (from a phenyl group to an ethyl-phenyl-ethyl group), and the number of binding sites (one vs. three) on the sensitivity and the selectivity of the sensor system are examined. Surprisingly, the Ru(bpy) 3 chromophore systems were also strongly selective for Cu(Il), Co(II), and Ni(II). The sensitivity of the sensor was increased by an increase in the number of binding sites, and decreased by the decrease in electronic coupling that was a result of adding the ethyl groups to the spacer portion of the molecule The photochemical and photophysical behavior of dodecafluorosubphthalocyanaoto boron (III) chloride is examined in the last section. The absorption maximum of the complex is 570 nm, and the luminescence mirrors the absorption with a maximum at 586 nm (Stokes shift 480 cm-1). The emission is strong, with a quantum yield in deaerated acetonitrile of 0.66 and a lifetime of 2.6 ns. The complex exhibits a reversible one electron reduction (E o = -0.53 V vs. SCE) and this, combined with the high singlet energy, indicates that the emissive excited state is a strong oxidant. Evaluation of the free energy dependence of the emission quenching with a series of donors yields a value of 1.7 V vs. SCE for the excited state reduction potential