We have investigated the dewetting morphology of thin films of the liquid crystals 5AB₄ and 5AB₃, from a silicon substrate. For 5AB₄, nucleation and spinodal dewetting can be clearly identified, and from scanning force microscopy of the liquid profiles, details of the effective interface potential can be quantitatively inferred. Due to peculiarities of the wetting forces in this system, the analogy to spinodal decomposition is particularly close. With 5AB₃, an additional, rather complicated dewetting scenario is observed which is connected to the crystallization of droplets which have formed during the initial dewetting process.