We report herein a synthetic pathway to new 7-bromo-1-(4-methoxybenzyl)-5-methyl-imidazo[1,5-a]imidazole-2-one. The synthetic potential of this scaffold was demonstrated by displacing bromine by Suzuki–Miyaura cross-coupling reactions. A large panel of boronic acids (aryl, heteroaryl or vinyl) were easily introduced, giving access to a broad and diversified library of 1-(4-methoxybenzyl)-5-methyl-7-(substituted)-imidazo[1,5-a]imidazole-2-ones.