Former Fine Gael politician Liam Cosgrave and businessman Jim Kennedy are due in the Supreme Court to try and stop their trials on corruption charges.
They are appealing against a High Court ruling dismissing their challenges.
Ex-TD and Senator Liam Cosgrave is trying to stop his trial on five charges of receiving corrupt payments in 1992 and 1997 in relation to land rezoning in Carrickmines, South Dublin.
Businessman Jim Kennedy is alleged to have made corrupt payments to politicians.
Their respective trials were due to go ahead in the Circuit Court last October but they were pushed back because of this appeal which is to be heard over two days by five judges of the Supreme Court.