Raynier Fernandes began his football career with Air India before representing Maharashtra in the Santosh Trophy. His breakthrough season came in 2017-18 with Mohun Bagan AC.
Florentin who is the brother of France World Cup winner and former Manchester United midfielder Paul Pogba will further strengthen the Mariners' defence which was bolstered by the addition of Australian defender Brendan Hamill on Thursday.
The Sydney-born, 29-year-old defender started his career by playing in youth academies and lower division clubs in Australia and made his professional debut at Melbourne Heart FC (now rebranded as Melbourne City FC) in 2010.
The 33-year-old has represented ATK, ATK Mohun Bagan and Odisha FC in the Indian Super League in recent seasons, and is a product of the Real Madrid Castilla.
Aakash Sangwan is fourth defender signed by Chennaiyin this summer, promising West Bengal youngster Sajal Bag, becomes the seventh midfielder to join the club.
The 23-years-old full-back has been an important player for the Hyderabad FC over the last two seasons and he played a crucial role in winning them their first-ever ISL title in the 2021-22 season.
The arrival of Das, who has previously featured for three of India's top football clubs--Mumbai City, East Bengal and Mohun Bagan--will give further fillip to Chennaiyin's midfield.
The Goa-born forward although is not a stranger to the Salt Lake Stadium, having featured for his club side ATK Mohun Bagan in the recently-concluded AFC Cup group stage matches.