Thiam blamed ‘judicial harrassment’ for his decision to leave the presidency of the Democratic Party of Côte d’Ivoire (PDCI).
The PDCI was due to meet on Monday to name an interim leader.
Thiam’s presidency was already the subject of a court challenge. A party activist petitioned court questioning the legality of his election as party leader in December 2023.
It is the latest roadblock the former banker has faced in his quest to become Ivory Coast’s president.
Last month, a magistrate in Abidjan invoked the country’s nationality law to order Thiam’s removal from the voter’s register, effectively ending his bid for the presidency.
Thiam held French citizenship before renouncing it to become Ivorian. In a video statement Sunday, Thiam said he was the target of a harrassment campaign.
He accused his attackers of instrumentalizing the judiciary.
