The Portuguese coach, set to return to Stamford Bridge later this summer, has already begun to draw up a list of players he wants to sign and has apparently targeted Porto defender Mangala.
The 22-year-old is highly rated and reports say he has a £30million buy-out clause in his Porto contract in a bid to ward off potential suitors.
Chelsea would not want to pay that much and will hope an offer in the region of £10million would be enough to land the Frenchman.
The France Under-21 international, who joined Porto from Standard Liege for £5.5m two years ago, has admitted to being flattered by Chelsea's interest and appears keen on teaming up with Mourinho for the new season.
He said: "It's flattering because Chelsea are a great club and Mourinho is a great coach. I intended to stay in Porto but you never know what will happen in football, especially when big clubs are involved.
"At Porto I play every week and I am involved in the title fight and the Champions League. And that is important to me."