The Leopards came from behind to book a ticket in the last four after defeating their opponents at the Stade Olympique Alassane Ouattara.
The Congolese weathered early pressure from the Syli Nationale before taking control of the tie.
Guinea led through Mohamed Bayo's 20th minute penalty after he was fouled in the box.
The Guineans were awarded a penalty after Mohamed Bayo fell in the penalty box following a touch from Chancel Mbemba.
A penalty was overlooked initially but after a VAR review, it was awarded. Mohamed Bayo converted calmly to put Guinea into the lead.
But DR Congo captain Chancel Mbemba rose highest to power home an equaliser from a corner just seven minutes later.
After the break, the Leopards turned the screw. Cedric Bakambu should have put them ahead when he missed a golden chance before Sekou Sylla fired off target for Guinea.