<p dir="ltr">This thesis introduces the synthesis and characterisation of new rhodamine and fluorescein based phosphine ligands and their transition metal complexes, and reports the fluorescent properties of selected phosphine ligands for detecting metal ions as fluorescent chemosensors.</p><p dir="ltr">Rhodamine and fluorescein are common xanthene dyes bearing excellent photophysical properties. Rhodamine and fluorescein derivatives are widely applied as fluorescent chemosensors. Upon addition of the analytes (e.g. metal ions), a fluorescent enhancement can be observed accompanied with an obvious colour change, which is due to the ring-opening process of their famous spirolactam framework. Tertiary phosphines (PR3) are an important type of ligands which can bind to transion metal ions. [Continues.]</p>