IT services firm Mindtree on Friday named Debashis Chatterjee as its new Managing Director and CEO. Chatterjee, who previously led the digital systems and technology practice at Cognizant, will become Mindtree's third CEO in its two-decade existence. He replaces Rostow Ravanan, who quit along with Chairman Krishnakumar Natarajan and Vice Chairman NS Parthasarathy after L&T's hostile takeover.