The Blues attempted to sign the Frenchman during the January transfer window but were unable to get a deal over the line.
With just less than six months remaining on his contract, the Catalan giants were willing to sell Dembele for €10m, but the attacker turned down the move.
The 24-year-old is likely to pursue a free transfer. Despite being failed to land him in January, the Premier League giants are planning a fresh approach.
Chelsea head coach Thomas Tuchel previously managed Dembele at Borussia Dortmund, and the German tactician is reportedly keen on a reunion with the 2018 World Cup winner next term.
Chelsea could face stiff competition from Paris Saint-Germain, who were also in the race to land the attacker, but the attacker was keen to see out the season before deciding his future.