"In my opinion, Motorola should be split into separate companies: a mobile devices company; an enterprise mobility company; a connected home company; and a company focused on mobile networks infrastructure," said the billionaire investor, who holds about 3 percent of the company.
Icahn, whoon Motorola's board in May after a bitter battle, said in a statement the changes revealed on Friday were at the company, which also makes set-top boxes and network equipment.
"The best opportunity for the mobile devices' business to attract top-flight management and to prosper and grow is to establish it as a standalone business," he said.
Motorola announced on Friday that Zander, who was chief executive for four years,
"Although I like Ed Zander personally, I never thought that he was the right man for the job," Icahn said.
The investor and his affiliated companies held 60.5 million shares in Motorola and was its sixth-largest shareholder on September 30, according to Thomson Financial analytics.
Motorola declined to comment on Icahn's statement.
Motorola has a market capitalization of $36.5 billion based on Friday's closing share price of $15.97 and a share count of 2.284 billion shares, according to Reuters data.