Mohammad Khazaei, 42, and Saeid Moradi, 29, are among five Iranians suspected of involvement in the February 2012 blasts, that followed attacks in India and Georgia and saw Tehran accused of a terror campaign.
The pair have already pleaded not guilty at a court in Bangkok to charges including attempted murder and possessing explosives, their lawyer Kittipong Kiattanapoom told AFP.
"They were not involved with the bombs nor did they aim to kill any innocent people, including police officials," he said outside the court.
Kittipong also said the men had not rented the suburban Bangkok house, where an apparently unintended explosion disclosed the supposed plot.
He said Moradi, who lost both his legs in a subsequent blast, had been surprised to discover bombs in a cupboard of the property.
The injured suspect had been trying safely to dispose of one device when it fell to the ground and detonated on the street, Kittipong added.
Israel blamed the February 14 Thai blasts, and bomb attacks a day earlier targeting Israeli embassy staff in India and Georgia, on Iran.
Tehran denies the allegations.
In June a Malaysian court ordered the extradition to Thailand of another Iranian suspect Masoud Sedaghatzadeh, who was 31 at the time.
Sedaghatzadeh was arrested at Kuala Lumpur's international airport a day after the Bangkok blasts. Two other suspects are believed to have returned to Iran.
The court hearing resumes Wednesday.