Pep Segura, Barca's general manager, said negotiations with Liverpool for Brazilian playmaker Coutinho and Borussia Dortmund over a deal for promising French winger Dembele could be finalised within days.
"We have to help the team with reinforcements and they will be here in the coming days," Segura told Catalan TV station Esport3 after Barca lost the second leg of the Super Cup 2-0 at Madrid's Santiago Bernabeu.
"We are discussing the conditions of Coutinho and Dembele...they are close.
"We hope they will be Barca players next season."
Barca's season has been thrown into turmoil by Neymar's world record 222 million euro ($261 million) move to Paris Saint-Germain earlier this month.
New Barca coach Ernesto Valverde admitted Neymar's absence has affected the balance of the side.
Meanwhile, the Catalans have struggled to close deals for Coutinho and Dembele with Liverpool and Dortmund holding out for fees in excess of 100 million euros in the knowledge of Barca's desperation to land a replacement before the transfer window shuts on August 31.
Barca defender Gerard Pique denied reports there is a growing feud between club's players and under-pressure board.
However, Pique admitted Barca have plenty of work to do if they are to close they gap on Madrid, who have added to their crowns as European and Spanish champions by winning both the UEFA and Spanish Super Cups in style over the past week.
"We are not in the best moment. Not as a team or as a club," said Pique.
"We have to stick together and move forward.
"The season is long and it has just begun. Madrid were superior so we have to live with defeat, congratulate them and improve."