Of all transition metals, gold has long sustained attention owing to its unique chemical and physical properties. Beyond that, the ease of processing gold allows its use in science, industry, and in various chemical, biological, and medical applications. For example, gold is used in medicine to treat rheumatoid arthritis, asthma, cancer, and brain and skin lesions. However, the extensive use of gold compounds can adversely impact the natural environment and biological systems due to their potential toxicity. For those reasons, identifying trace amounts of gold species in solution and cell media is crucial. Unlike the detection methods of atomic absorption spectroscopy, atomic emission spectroscopy, and inductively coupled plasma spectrometry, fluorescence-based detection methods offer easy sample preparation, rapid response, high sensitivity, reproducibility, and efficiency, all at a low cost. Today, various types of fluorescent sensors selective to gold ions have been designed, typically with BODIPY, fluorescein, rhodamine, naphthalimide, and coumarin-based fluorophores. In the work for this thesis, for the first time an enyne-derived BODIPY-based sensor was designed and synthesised to identify Au3+ ions, after which photophysical changes in the presence and absence of the analyte were examined both in solutions and in cells.