a b s t r a c t The reactions of N,N 0 -bis(salicylidene)propane-1,3-diamine (salpropH 2) and its substituted derivatives with Ga(acac) 3 afforded the complexes [Ga(acac)(salprop)]Á0.5H 2 O (1), [Ga(acac)(5Clsalprop)] (2), [Ga(acac)(5Brsalprop)] (3), [Ga(acac)(5NO 2 salprop)] (4) and [Ga(acac)(5Mesalprop)] (5), in high yields. The crystal structures of all complexes have been determined by single-crystal X-ray crystallography. All complexes are mononuclear with the Ga(III) atoms being in octahedral environments surrounded by one tetradentate chelate 5Rsalprop 2À ligand and one bidentate chelate acac À ligand. The free ligands exhibit photoluminescence which was found to be increased upon complex formation. The substituted derivatives of the salpropH 2 ligand bearing either electron-donating methyl groups or electron-withdrawing groups, such as Cl, Br and NO 2 at the fifth position of both salicylidene rings were found to modify the emission maximum of the free ligands and the complexes.