The Draconians come from the planet Draconia and are a very technical species. They have lots of technology including Laser Weapons and Intergalatic Space Travel. The Draconians formed an alliance with Earth so Humans and Draconians were friends.
The Doctor once helped Draconia as there was a space plague. He cured the Draconians and they made the Doctor a nobleman of the Draconian Empire.
The Draconians were almost dragged into an Intergalatic war by the Doctor's greatest enemies the Daleks. The Daleks alongside there ally the Master plotted against the friendship between Draconia and Earth. The Master used a Sonic Hypnosis to make humans see Draconians killing them. It was actually the Ogrons in disguise. This started a hate between Draconia and Earth so the Doctor was accused of it so he was put into a prison.
When the Doctor escaped he travelled along with Jo Grant to Draconia to tell the Emperor that it was actually the Master tricking them. When some of the Ogrons disguised as Humans entered the royal throne room an Ogron was killed and the Draconians learned that it wasn't the Humans it was the Master. When the Humans figured it out the Draconians and Humans were once again friends. They fought against the Daleks together once again.
They have appeared in:
Season 10: Frontier in Space