We have shown that this pressure could be increased by dilution of a layer with a stearic acid. Guest-host floating layers with increasing amount of fatty acid show increase of a surface pressure at the isotherm bend point and increase of the peak layer compressibility (Figure ). The latter does not fall below zero for 1:3 stearic acid layer. However, changes in luminescence and UV-Vis absorption in host-guest system after collapse are close to a pure layer (discussed later). This emphasizes fact of low co-organization happening between host and guest. Perhaps the acid exists as a separate layer, whereas chromophore units are still prone to interactions with water and between each other (at a corresponding compression). Aggregated floating layer is still elastic after the negative compressibility region, but pronounced hysteresis in multiple compression-relaxation isotherms shows that once aggregates are formed, structure does not relax anymore. This may be described in two different ways -molecules may quickly form 2D rafts at a limiting compression or may form 3D structures. Consistently observed raise in isotherm after 80 Å2 /m corresponding to rectangle of a molecule projection, suggesting the raft formation variant to be more probable.