He was the author of several Romanian language instruments, published under the aegis of the Romanian Academy (including Dicționarul limbii române - "Dictionary of the Romanian Language", Micul Dicționar Academic - "Concise Dictionary of the Academy" and Îndreptar ortografic, ortoepic și de punctuație - "Guide to Orthography, Orthoepy and Punctuation").
He was a staunch adversary of the fascistIron Guard, and supported RectorTraian Bratu in his confrontation with the latter.[9] When the Guard came to power in 1940 (see National Legionary State), Iordan was subject to an inquiry, which decided in favor of his early retirement; he was reinstated in 1941, when the government was replaced at the end of the Legionary Rebellion,[10] and, despite later claims that he was an active opponent, kept a low profile during Ion Antonescu's dictatorship (see Romania during World War II).[11]
Iordan was appointed ambassador to the Soviet Union in August 1945 — during a period when left-leaning intellectuals became the predilect candidates for the diplomatic corps.[14] He resigned in 1947, a gesture which coincided with moves by the PCR to have diplomatic offices placed under tighter political control.[15]
Before his appointment to Moscow, Iordan was placed at the head of committees which were overseeing the purging of real or alleged pro-Nazis from educational institutions; although he faced criticism over his initial PSD affiliation (which was attributed to "his low ideological level at the time"),[16] following the establishment of a communist regime in 1947–1948, he was engaged in a campaign to uncover and take measures against political opponents and critics of totalitarianism.[17]
Among those whose career was affected a result of Iordan's verdicts was the writer Paul Goma (expelled from the Literature Institute for, among others, having questioned the scientific value of Moldovenism and the status of Russian as the foreign language of choice in Romanian schools).[21] After briefly serving as head of the National Theater Iași (in 1945, during the time when it had taken refuge in Sibiu), Iordan was also present on the board of Editura Cartea Rusă, which published works of Russian literature.[22]
In 1955, following Ion Nestor and Eugenia Zaharia's thesis regarding the Romanian specificity of the 9th-11th century Dridu culture (see Origin of the Romanians), he was appointed head of Comisia pentru studierea formării poporului român ("Committee for the Study of the Romanian People's Formation"), which signified an early move against the Stalinist rhetoric encouraged during the previous years, and an official rejection of Mihail Roller's views on the role of the Slavs in Romanian ethnogenesis.[23] Iordan himself supported the view that Romanians had been formed both north and south of the Danube.[24]
Toponimia românească, Bucharest, Editura Academiei, 1963.
Istoria limbii literare spaniole, Bucharest, Editura Didactică și Pedagogică, 1963.
Introducere în lingvistica romanică, Bucharest, Editura Didactică și Pedagogică, 1965 (in collaboration with Maria Manoliu).
Structura morfologică a limbii române contemporane, Bucharest, Editura Științifică, 1967 (in collaboration with Valeria Guțu Romalo, Alexandru Niculescu).
Scrieri alese, Bucharest, Editura Academiei, 1968.
Alexandru I. Philippide, Bucharest, Editura Științifică, 1969.
Crestomație romanică, vol. I-III, Bucharest, Editura Academiei, 1962-1974 (co-ordination).
Memorii, vol. I-III, Bucharest, Editura Eminescu, 1976–1979.
Limba română contemporană, Bucharest, Editura Didactică și Pedagogică, 1978 (in collaboration with Vladimir Robu).
Dicționar al numelor de familie românești, Bucharest, Editura Științifică și Enciclopedică, 1983.
Istoria limbii române (Pe-nțelesul tuturora), Bucharest, Editura Științifică și Enciclopedică, 1983.
Manual de linguistica romanica, Madrid, Gredos, 1989 (in collaboration with Maria Manoliu, Manuel Alvar).
Lucian Boia, History and Myth in Romanian Consciousness, Central European University Press, 2001 ISBN963-9116-97-1
Ovidiu Bozgan,『Traiectorii universitare: de la stânga interbelică la comunism』("University Trajectories: from Interwar Left to Communism"), in Lucian Boia, ed., Miturile comunismului românesc ("The Myths of Romanian Communism"), Editura Nemira, Bucharest, 1998, p. 309-335
Victor Frunză, Istoria stalinismului în România, Humanitas, Bucharest, 1990