The lads aged 17 and 24, both won plates in their first-ever fights.
Liam won all five rounds against a Fife opponent while David overcame two early round defeats to triumph in his final three.
His Stirling counterpart had struck a punch to his
face that made him wobble but he got back up and went on to victory.
Liam, whose involvement in the martial art was inspired by watching Bruce Lee films as a kid, said of his own achievement: "I was proud to win my first fight.
"My fight was before David's and I had a sore leg but I still rushed to get through and see him. He was determined to win."
The Grangepans duo now have their sights set on a Glasgow fight at the end of August.
Coach Alex Sneddon said: "Both of them did really well because it was their first fight.
The Thai Boxing Club meets at Bo'ness Recreation Centre on Tuesdays from 6.30-7.30pm and Thursdays, 8.30-9.30pm.
Find out more about what Bo'ness Recreation Centre has to offer by clicking
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