An Adelaide couple who lured the woman's ex-boyfriend to a remote location where he and a friend were set on fire has been sentenced to significant jail terms.

Kerry Leanne Ross and Ben Cody Woodhart — also known as Ben Corey Woodhardt — both aged 29, were found guilty of an aggravated charge of causing serious harm with intent and an aggravated charge of causing harm with intent.

The District Court heard the couple orchestrated a plan to lure Ross's ex-boyfriend to a remote location at Elizabeth North, in Adelaide's northern suburbs, in November 2013 and attack him.

The victim went to the location with a friend early in the morning, believing Ross wanted to buy drugs from him and potentially rekindle their relationship.

The court heard that after Ross and a female friend left the victims under the guise of retrieving a handbag, Woodhart and an accomplice approached the car, the accomplice poured petrol over the men through their open car windows and then set them on fire.

The court heard police knew the identity of the second man involved in the attack, but have not been able to find him.

Judge Rauf Soulio said it was a premeditated and "sinister" attack that had left the victims with severe physical injuries and psychological issues.

The court heard Ross's ex-boyfriend suffered third degree burns and was placed in an induced coma, while his friend was also badly burnt.

It heard both suffered from ongoing pain as well as nightmares and psychological trauma.

Offences 'carefully planned and calculated': judge

Judge Soulio described the victims' suffering as "traumatic" and said they were likely to suffer for the rest of their lives.

"It is difficult to understand the process of reasoning that resulted in committing crimes of this nature," Judge Soulio said.

"This was not opportunistic or spontaneous, nor was it carried out in a fit of anger.

"The offences were carefully planned, the offences were carried out in a calculated manner.

"The use of fire to cause the harm was sinister and may have led to the death of the men."

Judge Soulio sentenced Woodhart to 13 years and eight months' jail with a non-parole period of eight years and eight months.

He sentenced Ross to six years and nine months' jail with a non-parole period of four years and three months.

In setting a lesser sentence for Ross, Judge Soulio said he accepted she was under the belief the assault would be less serious and wouldn't involve the use of fire.

He also acknowledged her remorse and "belated contrition".

The court heard Ross and Woodhart had married since the incident.