The former Falkirk youth player headed in a Neil McCann free-kick in the 54th minute and Scott Arfield's late penalty confirmed the May 30 meeting with the Light Blues.
The Bairns' deserved victory also ensured they will compete in Europe for the first time in next season's Europa League.
It was a good afternoon's work for boss John Hughes who has been fighting a battle with some disgruntled Falkirk fans in recent weeks after his side found themselves bottom of the SPL.
However, by making history, Hughes will surely buy himself some time even if the Bairns fail to beat the drop.
Only one Falkirk player left Hampden disappointed, Arnau Riera, who will miss the final after picking up a booking, his third in the competition but unfortunately for the midfielder, his bad luck will not dampen the enthusiasm at the club as they look forward to their first final appearance since they lost to Kilmarnock in 1997.
The crowd of 17,124, disappointing as it was, cheered a frantic start to the game as both sides careered forward with abandon but that enthusiasm soon waned as a mediocre first half unfolded.
Falkirk's burly striker Michael Higdon cracked the post in the 10th minute with a right-footed shot from 20 yards.
Seven minutes later Arfield tried his luck from distance, this time Pars' keeper Paul Gallacher had to dive to his right to parry clear.
Midway through the first half, with finesse still at a premium, Dunfermline defender Calum Woods picked up a needless booking for a foul on Neil McCann 40 yards from goal which would have left him out of the final had the Fifers triumphed.
Fifers' midfielder Alex Burke sent in a shot from distance that was redirected inside the box by Graham Bayne, but wide of the target.
Four minutes from the break, Gallacher did well to block a close-range shot from Carl Finnigan after the Dunfermline defence had fallen asleep.
Three minutes into the second half, Riera, also on two previous bookings from earlier rounds, found himself banned from the final when he got himself booked for diving at the edge of the Dunfermline box.
Scobbie picked up a deserved yellow card soon afterwards for a hefty challenge on Nicky Phinn but the defender was celebrating in the 54th minute when he dramatically put the Bairns ahead with his first goal of the season.
After Austin McCann had fouled Finnigan, veteran midfielder McCann flighted a free-kick in to a packed Dunfermline box and Scobbie rose highest to thunder a header past the helpless Gallacher.
The Falkirk-born player was submerged under a pile of dark blue jerseys as the Bairns fans went wild.
Jim McIntyre put on Greg Ross, Andy Kirk and Rory Loy for Scott Thomson, Steven Bell and Jamie Mole respectively.
The Pars pushed bodies forward in search of an equaliser and in the 79th minute Loy headed over from close range after latching on to a Scott Wilson flick.
The final 10 minutes were tense, with both teams stretched and Falkirk threatening on the break.
However, in the 89th minute Ross compounded a miserable day for the Pars when he fouled McCann in the box to concede a penalty.
Arfield slammed home the spot-kick and that was the Bairns' final place confirmed although there was time for Gallacher to pull off a fine injury time save from Higdon.