Organization of a Linear polysilane chain in a spincast film was controlled in response to the surface photochromic reaction of an azobenzene (Az)-containing monolayer. The kinetics of crystallization as well as the final ratio of crystalline/disordered of poly(di-n-hexylsilane) depended strongly on the geometry of the Az unit. The in-plane chain orientation was controlled by preillumination with linearly polarized light, with the polymer chain direction aligning perpendicular to the polarization plane of irradiating light. This principle could be utilized in a microscopic patterning of the chain orientation, a result which would be difficult to achieve using conventional mechanical alignment techniques.