The Portuguese coach departed Stamford Bridge on Wednesday night after texting five senior players to say he was leaving.
Mourinho caught Chelsea's hierarchy by surprise after the premiere of the club's documentary 'Blue Revolution' by demanding talks at Stamford Bridge over his future.
Those talks continued late into last night, but his players were left in no doubt that the 1-1 draw against Norway's Rosenborg in the Champions League on Tuesday night was his last match in charge.
Mourinho is understood to have sent text messages to five players at 6pm on Wednesday night and by midnight the entire first-team squad were aware that he had left.
Chelsea are currently fifth in the Premier League, two points behind leaders Arsenal after six games, and their 1-1 draw with Rosenborg in their opening Champions League game on Tuesday night did not help his cause.
Mourinho's departure comes just days before they face Manchester United at Old Trafford.
Assistant Steve Clarke or director of football Avram Grant are set to take charge of team affairs on Sunday.