A new Schiff base ligand 2-(6-((E)-1-(2-heptadecylcarbonyl-oxyphenyl)methylideneamino) [1,10] phenanthrolin-5-yl-imino-methyl)phenyl stearate has been synthesised from the reaction of 5,6-bis(salicylideneimino)-1,10-phenanthroline with stearic acid. The ligand reacts with Co(II), Ni(II) and Cu(II) salts to form complexes. The ligand has been characterized by FTIR, H-1 NMR (DMSO-d(6)). UV-vis and mass spectra, elemental analysis and fluorescence spectrophotometry. Protonation constants of the ligand and overall formation constants of the complexes have been calculated from potentiometric data using a computer program.