Abstract: The present technology is directed to capillarity-based devices for performing chemical processes and associated system and methods. In one embodiment, for example, a device can include a first porous element having a first pore size and configured to receive a fluid at its proximal portion, and a second porous element having a second pore size greater than the first pore size and configured to receive a fluid at its proximal portion. The first porous element can be positioned across the second porous element such that an overlapping region exists between the porous elements where the porous elements are in fluid communication. Before delivery of the fluid to the second porous element, the fluid pressure at the overlapping region is greater than the capillary pressure of the second porous element such that a fluid delivered to the first porous element wicks through its overlapping portion without wetting the second porous element.