The Real Madrid boss is expected to be named as the new Stamford Bridge manager next month, and the report claims he's prioritised the signing of Mangala from the Portuguese champions.
But the 22-year-old French star will not come cheap. Porto are notoriously savvy negotiators, and L'Equipe claim they're holding out for €35m.
The spending restrictions imposed by Financial Fair Play could stop Chelsea from splashing out, with the club keen on other targets as well.
A new striker is thought to be high on the list of priorities, while Mourinho will likely want to assess and strengthen the squad significantly on his arrival.
Mangala's impressive performances in Portugal have been rewarded with a first call up to the France senior squad. The young defender will be hoping to make his international debut in one of the two friendlies against Uruguay or Brazil.
Porto signed the centre-back for just €6.5m from Belgian club Standard Liege in 2011, and the French international has become a star this season after his first campaign largely restricted him to a substitute role.
Chelsea have a history of purchasing players from Porto - particularly after Mourinho first took charge in 2004.
Paulo Ferreira, Ricardo Carvalho, Deco, and Jose Bosingwa have all completed the switch from Porto to Stamford Bridge in the past 10 years.