An organic thin film includes an organic solid crystal material and has mutually orthogonal refractive indices, nx, ny, and nz each having a value at 589 nm of between approximately 1.5 and approximately 2.6, where nx≠ny≠nz. The organic thin film may be birefringent, and may be configured as a single layer thin film, or plural organic thin films may be stacked to form a multilayer that may be incorporated into an optical element, such as a reflective polarizer.