The CPI-M leader was arraigned as the seventh accused in court. He, however, approached the CBI court with a discharge petition saying he has done no wrong.
Vijayan, as the power minister, had signed the agreement in 1997 for renovating three power plants in the state with SNC Lavalin, which was later shrouded in controversy.
The verdict is being seen as politically significant development as it could pave the way for Vijayan's return to the electoral scene as the central player of the Left Democratic Front.
Welcoming the decision of the CBI court, CPI-M politburo member S Ramachandran Pillai said, “Our stand that it was a politically motivated case has proved right.”
(With agency inputs)