The photophysical behaviour of Schiff-base complexes with several different metals has been investigated. Among these complexes, the one with aluminium (3) presents interesting features, showing good chemical stability, high absorption coefficients and fluorescence quantum yield. In addition, the fluorescence intensity of 3 udergoes appreciable changes in the presence of coordinating species, such as carboxylate anions, allowing the association process to be monitored with high sensitivity. In addition, we have demonstrated that, if suitable groups are attached to the carboxylate function, supramolecular systems with interesting properties can be designed and characterised.