Aryl Schiff bases compounds derived from sulpha drug derivatives (sulphonamide I, sulphadiazine II and sulphamethaxazo1e III) with salicylaldehyde were prepared and investigated by different spectroscopic techniques (Uv - vis. İR, 'H- NMR) and elemental analysis. The effect of solvent polarity parameters, metal ion and electron acceptor were studied, the study was extended to evaluate the dissociate constants (pKa) values of these compounds using spectrophotometric studies.