Mixing dining chairs allows you to give your dining room more character and personality. It also enables you to create a look, which is less predictable and more appealing to the eye.
Leather + fabrics serve as a great unpredictable pair for a dining space.
Using the same style chairs in different variations of colors and textures provides a uniform look with an alternative look.
Woods and different weave variations give a natural cohesive look while still encompassing an element of interest.