Le Corbusier and Kahn are two of the most distinguished architects who had employed natural lighting on the expressive dimension of Architecture. Despite the general impression given by previous literature about the resemblance between the two architects regarding natural lighting in Architecture, this research focuses on the problem of the inadequacy of the knowledge about the two architects variance regarding the expressive properties of natural lighting in their works and adopts defining this variance as its objective. The research adopts the approach of light zones and employs the relevant computer program for representing and analyzing natural lighting. And through a comparative study for two cases, the conclusions about the variance between the two architects, regarding defined variables representing a group of natural lighting properties, related to the expressive dimension of architecture, are introduced.

Key Words: Natural Lighting, Expressive Dimension of Architecture, Light Zones.