It will be a Malone versus Ballynahinch First Trust final at the Kingspan on Wednesday, December 10 after the Gibson Park team eliminated Ballymena 17-13 and Hinch needed three minutes of injury time to defeat City of Derry 19-14.
Ballymena, the trophy winners in two of the past three seasons, showed little of the form that has taken them to second in the AIL 1B.
"I am very disappointed," commented Ballymena Director of Rugby Pete McKenzie. "We missed so many scoring chances and in the end they came back to bite us."
Ballymena were ahead with a Timmy Small penalty after three minutes before Malone hooker Darryl Maxwell crashed over from a maul for Neil Burns to goal.
After 30 minutes he added a penalty to give his team a 10-3 interval lead. Ballymena levelled when a Matthew Rea break inside his own territory resulted in Martin Irwin touching down for Small to goal.
He then regained the lead with a penalty before the visitors retorted with an excellent effort when Andy Burgess gathered a kick ahead inside his '22'.
He saw space and his momentum took him through before slipping the ball to Michael Barker, who went in for Burns to convert.
Malone PRO Raymond Thomas said: "They threw everything at us towards the end. We managed to hold on and are now at Kingspan for the first time in five seasons due not only to the squad but also to the expertise of our coaching team under Jacques Benade."
Last season's defeated finalists Ballynahinch were fortunate to overcome a gallant City of Derry at Ballymacarn Park.
The first half was a tame affair with Hinch's Chris Quinn kicking three penalties to Andrew Semple's two. After the restart Derry were fired up and in the 51st minute right winger William McCleery landed a try.
Quinn and Semple then swapped penalties before Hinch ran in that deciding try. In the final quarter Derry were encamped around the home '22' but then they conceded a penalty for not releasing.
A quickly taken penalty and six phases later they had brought play to around halfway. They had extra numbers on the right and finally Paul Pritchard crossed in the corner for Quinn to goal.