The linearly polarized light induced photoalignment of liquid crystals is critically influenced by the structure of polymethacrylates with coumarin side chains. While the photoalignment direction is in parallel with the electric vector of linearly polarized 313 nm light fur polymethacrylates having coumarin moieties with ethylene and hexamethylene spacers, the reversion of photoalignment from parallel into perpendicular orientation is observed for a polymethacrylate having coumarin side chains without spacer.