The colonel and major were deployed with the gendarmerie, which was then part of the army, in the northeastern city of Erzurum, the state-run Anadolu news agency said.
They were charged with violating the constitution. After the coup, the gendarmerie was brought within the control of the interior ministry.
Ankara blames the attempted putsch on the US-based Islamic preacher Fethullah Gulen and has embarked on a relentless purge to eradicate his influence from public life. Gulen denies the charges.
Turkey detains business executives in Gulen-linked probe
Turkey's parliament on Tuesday approved a government-backed motion to extend by another three months the state of emergency imposed in the wake of the July 15 attempt to overthrow President Recep Tayyip Erdogan.
According to the latest figures published by Anadolu, more than 41,000 people have been arrested over suspected links to Gulen within the state of emergency.
With a record number of suspects behind bars, the trials are only now getting under way and are expected to last for months.
Twenty-nine Turkish police officers went on trial on December 29 in Istanbul accused of failing to defend Erdogan during the failed coup, the first such case in the city.
Turkey again extends emergency rule by further three months
There has been growing international alarm over the extent of the crackdown amid the state of emergency imposed after the coup, with critics concerned it has been used to target Erdogan's opponents.
Erdogan has said there are strong public demands for retribution even extending to reimposing the death penalty.
One of the main trials will begin on February 20 of 47 suspects accused of trying to assassinate Erdogan at a holiday resort.
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