The Guardians of Scotland Trust is urging Lotto players to boycott the UK National Lottery for a week and donate £4 to their project instead.
The Trust, which consists of historians and politicians from a number of parties, decided to make the unusual request when it discovered its bid for lottery funding had been turned down.
Trust members hoped to create a public artwork to mark William Wallace's victory over the English forces at the Battle of Stirling Bridge in 1297.
The Heritage Lottery Fund (HLF) awards grants to support projects that sustain and transform the British heritage. The Battle of Sterling Bridge (depicted by Mel Gibson in the film Braveheart) has great historical importance, so the project should have been a good match for the HLF's mission statement, but the HLF (Scotland) said it is 'concerned about the level of confirmed partnership funding' for the Stirling project.
At the present time there is nothing at the site to mark Wallace's victory and the Guardians of Scotland Trust now fears it will be unable to mark the site with a permanent art fixture if the funding shortfall of £72,000 is not found by August 23, 2014.
Creative Scotland has pledged to supply £137,000 to the bid, but only its funding is matched.
Guardians of Scotland Trust spokesman John Robertson said: ""At the moment, there is nothing at the north side of Stirling Bridge to mark this important historical event. Tourists come looking for information to this site on the outskirts of Stirling and are met with a blank canvas."
Leading historian Sir Tom Devine said: "The Battle of Stirling Bridge is second in importance only to Bannockburn in the Wars of Independence. It is imperative that the location should therefore be marked in a suitable fashion."