Between 1969 and 1971, he was a founder of the clandestine National Patriotic Front of Bessarabia and North of Bukovina, established by several young intellectuals in Chişinău, totaling over 100 members, vowing to fight for the establishment of a Moldovan Democratic Republic, its secession from the Soviet Union and union with Romania. After the NPF leadership got in touch...In December 1971, following an informative note from Ion Stănescu, the President of the Council of State Security of the Romanian Socialist Republic, to Yuri Andropov, the chief of the KGB, Ghimpu as well as Alexandru Usatiuc-Bulgăr, Valeriu Graur, and Alexandru Șoltoianu were arrested and later sentenced to long prison terms. He was sentenced on 13 July 1972. Ghimpu spent six years in prison (1972–1978), as result of his political activities.
