A pair of consequential featherweight bouts have been booked for UFC 164 in Milwaukee.
Mendes (14-1) has been looking to work his way back to another title shot since his Jan. 2011 loss to featherweight champion Jose Aldo Jr. He's won three straight fights since that time, the most recent being a first-round finish of Darren Elkins at UFC on Fox 7 on April 20 in San Jose.
Mendes was originally slated to fight Guida on that date, but Guida pulled out with an unspecified injury and Elkins took his place.
The veteran Guida (30-13) is at an important juncture in his career. A fighter once best known for exciting battles, he's played it safe in recent fights to mixed results: A loss to Gray Maynard last year and a win over Hatsu Hioki at UFC on FOX 6.
Koch vs. Poirier, a bout at one point slated for UFC 143, is a matchup between fighters who a year ago seemed destined for the top, but both hit stumbling blocks.
Koch (13-2) was twice scheduled to face Aldo for the title in 2012, but both times had the bout canceled, first because of an Aldo injury and second because of a Koch injury. When Koch returned in January, he lost a second-round TKO to Ricardo Lamas.
Poirier (13-3), meanwhile, has dropped two of three fights since starting off his career at 12-1. He lost to Chan Sung Jung last May via fourth-round submission in the MMAFighting.com Fight of the Year. He returned in December and defeated Jonathan Brookins, then lost a decision to Cub Swanson on Feb. 16 in London.