The 25-year-old is set to become one of Europe's most attractive transfer targets come the end of the season, when he will be available for €25 million (£19.8m) due to a buyout clause in his current deal at Signal Iduna Park.
Bayern Munich officials have been open in sharing the Bavarian club's interest in a deal for Reus, who could follow former Dortmund colleagues Mario Gotze and Robert Lewandowski to the Allianz Arena.
And Bayern's hopes may have been boosted after Chelsea's manager played down talk Reus had interested those in the Stamford Bridge corridors of power.
Mourinho was blunt when asked of any potential interest in the attacker, as he said on Monday: "We don't want Marco Reus.
"The market is closed and the player belongs to Borussia. We have top players in this position.
"We are not interested, not at all."
Chelsea face former manager Roberto Di Matteo at Schalke on Tuesday, looking to secure a place in the UEFA Champions League last 16.
Victory in Gelsenkirchen or a draw in which they score at least twice will do the job for Mourinho's side, but the Portuguese remains wary of being eliminated.
"We have two matches to qualify, but it would be better for us to qualify [on Tuesday]," said Mourinho.
"We have so many matches in December so if you can avoid a crucial final match where you need to qualify against Sporting and avoid that pressure it would be very good for us.
"We will try to qualify [on Tuesday]. This team is in a state of evolution. To go into the Europa League would be very bad for this team.
"Evolution gets faster when you are playing in the best competitions. It would be very disappointing if we went into the Europa League."
