He had just returned from France where he received heart treatment for two months.
Mr Gon Coulibaly had been chosen as the governing party’s presidential candidate for an upcoming election in October 2020.
H was chosen after President Alassane Ouattara said he would not contest for a third term in office.
President Ouattara said the country was in mourning.
He said added that the 61-year-old had become sick during a weekly cabinet meeting and was taken to hospital where he later died.
This now brings uncertainties in the upcoming election which was to be held in October this year.
Mr Gon Coulibaly had received a heart transplant in 2012 and had travelled to Paris on May 2, 2020, for the insertion of a stent.
He returned last Thursday saying: "I am back to take my place by the side of the president, to continue the task of developing and building our country."
He was one of the favourites to win the presidential election.
Analysts have said earlier that if Mr Gon Coulibaly was unable to contest for the presidency, Mr Ouattara would have to run as a candidate since the party has no plan B.
But this will be a tough decision since Mr Ouattara made it known in March that he will not seek a third term. His decision not to run stunned the country.