Paulo Sousa will be presented as Fiorentina's new first-team coach on Monday after agreeing a deal to take over the Serie A side.
Fiorentina dismissed Vincenzo Montella earlier this month, citing a breakdown in trust after the ex-Italy striker was linked with Napoli and Milan.
Sousa then departed his role at Basel on Wednesday amid speculation he would succeed Montella - and his impending appointment was announced by Fiorentina on Sunday.
A club statement read: "ACF Fiorentina is delighted to announce that an agreement has today been reached with Mr. Paulo Sousa for him to become the new first-team coach of the Viola.
"Mr. Sousa will be in Florence tomorrow to complete the formalities.
"A news conference will be held at the Stadio Artemio Franchi tomorrow, Monday 22 June, at 19:00 [local time]."
Former Portugal midfielder Sousa played in Serie A for Juventus, Inter and Parma.
Prior to his solitary season in charge of Basel, where he won the Swiss Super League, he had taken charge of three clubs in the United Kingdom - QPR, Swansea City and Leicester City - in addition to Hungarian side Videoton and Maccabi Tel Aviv in Israel.
He will inherit a Fiorentina team that finished fourth in Serie A last term, securing a place in the UEFA Europa League.
