In 1975 Grigorian helped organize the group of free painters and sculptors in Tehran and was one of its founder members. Artists Gholamhossein Nami, Massoud Arabshahi, Morteza Momayez and Faramarz Pilaram were amongst the other members of the group.
Grigorian left Iran in 1977 at the age of 52. He lived for a short time in the United States before moving to Yerevan, Armenia, then still a republic of the Soviet Union. In 1989, he traveled to Russia at the invitation of the Union of Russian Artists, visiting Moscow and Leningrad.
He exhibited his clay and straw works in Yerevan in 1991. He later donated 5,000 of his artworks to the government of Armenia.
Some of his works are now on display at the Museum of Modern Art in New York, the Tehran Museum of Contemporary Art, the Museum of Contemporary Art in Kerman, and the National Gallery of Armenia.
He died on August 27, 2007 in Yerevan, at the age of 82.