Star saw off Premier League side Penicuik Athletic 1-0 at New Victoria Park to set up a clash with Dundee North End on Saturday, June 4, in the second biggest cup in Junior football.
Star's winner came midway through the first half when Grant Meaney got on the end of a great cross from Stuart Roseburgh to head powerfully into the net.
Penicuik were unable to find the leveller after the break as both sides ended the game with ten men. Newtongrange had Alan Brown sent off for dissent while Penicuik's Craig Miller was given a straight red card for a bad tackle.
New Newtongrange boss Alan Miller was delighted to reach the final. "It was a good win, not brilliant but as far as we are concerned the first step towards a good future next season," he said. "This is a good sign after a good performance at Hill of Beath last Saturday. The main concern is that we only had a squad of 12 players last night and we picked up another couple of injuries taking us down to ten. We now face Dundee North End in the final and it will be tough. They reached the final on merit but it's a huge incentive for us to take something from the season."
Penicuik boss Craig Meikle was disappointed with the result. "They had the better in the opening 45 minutes and deserved their lead," he said. "However, after the break we had at least three good chances to at least equalise but didn't take them. We now have to lift ourselves for our next semi-final in the Fife and Lothian's against Bo'ness on Monday. It's all about taking our recent good form into next season now."