A complete structural study of several homologous alkylcyanoterphenyls has been presented by Leadbetteret al.We draw here a comparison between this study and our own work for 4-n-nonyl-4″-cyanoterphenyl. Essentially we confirm the main results obtained by Leadbetteret al.but an additional E″ phase has also been studied by optical microscopy and X-ray diffraction. This phase with E symmetry but with a monolayer character hampers the study of the E′ phase and may prevent the observation of a devil′s staircase in this system.