Poirier (13-3) looks to rebound from a loss in his last outing to Cub Swanson at UFC on Fuel TV: Barao vs. McDonald on Feb. 16. Koch (13-2) is also coming off of a loss, having a four-fight winning streak halted by Ricardo Lamas at UFC on Fox 6 on Jan. 26.
Mendes (14-1) and Guida (30-13) were originally supposed to have fought at UFC on Fox 7 in April, but Guida pulled out of the bout due to injury.
Mendes enters the fight having won three consecutive bouts since failing to wrest the title from UFC featherweight champion Jose Aldo in January of 2012. Guida will be making his second featherweight start, having bested Hatsu Hioki in January.
UFC 164 does not yet have an announced main event.