We propose to synthesize a variety of lipophilic lithium ion fluorophores which will ultimately find use in applications of interest to cell physiologists, neuro scientists and to psychiatrists who treat patients manifesting manic/depressive psychosis. In Phase I, we have prepared several of these fluorophores. One of them has 5-fold greater Li/Na selectivity, based on a competitive extraction evaluation, than any lipophilic lithium ion carrier reported in the literature. This compound also responds to lithium ion with a significant increase in fluorescence. In Phase II, we expect to synthesize more of these compounds which are likely to improve on our Phase I effort with respect to selectivity and fluorescent properties. We will also explore the use of these compounds in devising a simple spot test for determination of lithium concentration in a drop of blood. Such a test which would not require a technician to draw blood samples could easily be performed in the psychiatrist's office to determine patient compliance with his/her lithium carbonate therapy. Other applications of these compounds including ion selective electrode (ISE) preparation and synthesis of water soluble analogs for use in cell physiology studies of the role of lithium ion in inhibition of inositol phosphate metabolism and other cell mechanisms will also be explored.