Shamrock Rovers dispensed with the services of manager Stephen Kenny during the week and will be looking to take another step towards silverware
Bohemians go into this game on a high after beating Shamrock Rovers on Monday. It was their first win in seven matches and some cup glory this season would be very welcome.
There is a dark mood around Dundalk and there is a growing sense of inevitability that they will be in the relegation play-offs.
The experienced Owen Heary looks set to miss out with a back injury for the hosts. For Dundalk Eoghan Osbourne is a doubt. Paul Whelan and Stephen Maher are both cup tied. It is a welcome relief for Dundalk from league struggles but Bohemians will be confident of prevailing.
Verdict: Home win
St Patrick's Athletic v Drogheda United
St Patrick's Athletic have not won the FAI CUP since 1961 and it remains a mystery why such a big and successful League of Ireland club finds the cup so elusive.
Liam Buckley is all too aware of that piece of history and will be confident of keeping up an excellent run of form at home against Drogheda United.
The Drogs have enjoyed a remarkable season and won 2-0 here in the league. Mick Cooke has a full squad to choose from apart from the four former Monaghan United players brought in to bolster the squad who are considered cup tied. Jake Kelly returns for the hosts and John Russell faces a late fitness test.
Verdict: Draw after 90 minutes
Shelbourne v Shamrock Rovers
Stephen Glass will take charge of Shamrock Rovers in a caretaker capacity for the first time hoping to galvanise the team to cup success. With the Airtricity Premier Division title firmly out of reach and even a European place in doubt, this match has taken on an extra importance.
Tolka Park has become a miserable place for Shelbourne this season with seven out of eight losses in the league. Paddy Kavanagh and Glen Cronin return for the hosts. Graham Gartland is out for Shamrock Rovers. Glass should be able to have an instant impact and secure a win and pile on the Tolka Park misery for Shelbourne.
Verdict: Away win
Derry City v Mervue Utd
It is three successive defeats for Derry City in what has largely been a disappointing season for the Candystripes. Injuries have been a big problem for Declan Devine's team but he should be able to steer them into the semi finals without too much trouble.
Stewart Greacen is supended for the hosts. Rory Patterson and Owen Morrison are still out injured. Mervue travel to Derry without the suspended Gary Kelly. Marc Ludden also misses out through work commitments.
Mervue Utd beat Waterford Utd comprehensively in the previous round and Derry City will be advised not to underestimate their opponents if they are to get to the semi final.
Verdict Home win