The two fifty-year-olds in 2012 paid a pharmacy in Thailand 20,000 kroner for what they thought were 30,500 tablets of 'blue valium', which they then tried to smuggle overland from Copenhagen airport to Oslo.
The Norwegian police stopped them on the train south from Oslo to Kristiansand, at which point they both admitted to smuggling valium.
However, when the police analyzed the tablets, they found that they did not contain the narcotic substance Diazepam. Instead, they contained chlorpheniramine, which is used to treat allergies.
Prosecutor Leif Aleksandersen told the local Fædrelandsvennen paper that the intention to smuggle itself constituted a crime.
"Both of them informed us that they had attempted to buy valium to sell in Norway. When they came home, it turned out that they had been fooled. That is why they are convicted of attempted smuggling," he said.
One of the men was convicted in 2014, but the other was only convicted in the last month.
"We had planned a hearing for February, but as the session was cancelled, we were not able to inform the accused of his charges," Aleksandersen said. "Apparently he was in Thailand. In the end, we held the hearing without his presence."
It is unclear if the man has returned to Norway to serve his sentence.