Electron spin resonance (ESR) spectroscopy has proved to be a powerful tool for the characterization of LangmuirBlodgett (LB) films. Since Cu cations are paramagnetic, ESR can be used to study Cu co-ordinated Schiff base materials. The physical and optical properties of bis-salicylidene hexadecylamino- copper(II), and poly(Cu-5,5'-methylenebis(N hexadecylsaliclidenamine)), LB layers have been discussed previously. The line shape of the asymmetrical spectra of the samples was shown by computer simulation to be Lorentzian. Spin concentrations were approximately one per molecule for LB films of both materials. The gfactors were considerably higher than expected for N or O heteroatoms containing cation- radicals. Magnetic resonance parameters and susceptibility were found to be sensitive to the sample orientation. Such behaviour is characteristic of ion-radical Cu-paramagnetic centres with spin S = 1/2 and anisotropic magnetic parameters oriented in a diluted magnetic system. The effective gfactor depended on the angle between the direction of an external magnetic field and the main molecular axis normal to the molecular plane. The central active fragment Cu is oriented parallel to the substrate surface, confirming the estimation of the orientation obtained by polarized visible spectroscopy, where a tilt of 13 degrees was found. The tilt angle is comparable with the one obtained from polarized visible spectroscopy. A possible explanation for the tilt in the polymeric LB films may be following: the average axis of the polymer chain is parallel to substrate surface, as suggested previously; however, because of the flexibility of the methylene group between the two benzene rings, the polymer chains adopts a 'zigzag' conformation in which Cu complex plane is effectively tilted.