The missiles were used to destroy a terrorist supply truck near Raqqa and a crane near the Omar oil field in Syria.
A pair of RAF Tornado GR4s launched the missiles after ensuring minimal civilian damage in the region.
UK Defence Secretary Michael Fallon said: "Britain is playing a key role in the fight against Daesh, whether helping Iraqi ground forces retake Ramadi or by striking targets near its Raqqa heartland.
"Our Reaper drones have now flown 1,000 missions against Daesh and we will maintain this tempo with RAF pilots flying day and night over Iraq and Syria."
The advanced air-to-ground radar-guided Brimstone missile can effectively strike fixed and moving ground-based targets, with height accuracy. It was developed based on the AGM-114F Hellfire missile of the US Army.
Brimstone is capable of destroying long-range targets with minimal collateral damage. It can be operated in all-weather conditions during day or night.
Measuring 1.8m in length and 0.18m in diameter, the Brimstone missile has a weight of 50kg and can travel at supersonic speeds while carrying a tandem-shaped warhead. The missile can engage a wide range of targets such as battle tanks, armoured vehicles and other fast-moving vehicles, bunkers, and naval vessels including fast-attack craft.
Image: Tornado GR4. Photo: courtesy of Crown Copyright.