New chloride- and bromide-modified metal-organic frameworks (MOFs) based on copper and 1,3-bis (carboxymethyl)imidazole (bcmim) derivatives have been prepared via post-synthetic modification (PSM) or by a direct route, following a simple, effective, and sustainable protocol. These materials have been characterized, and their catalytic activity has been studied. Cu-bcmim-Cl and Cu-bcmim-Br materials have been shown to be more efficient acidic catalytic systems than nonmodified materials. The catalytic activity has been tested as a Lewis acid catalyst in the methanolysis of styrene oxide and in the synthesis of quinolines and acridines, with the recovery and recyclability of the catalysts being possible. Furthermore, the catalytic activity of the catalysts has been tested in the oxidative coupling of formamides and carboxylic acids. This study enhanced copper-based metal-organic frameworks (MOFs) by incorporating chloride and bromide, leading to improved catalytic properties. These halide-modified MOFs exhibited increased microcrystallinity and superior performance in organic reactions, such as styrene oxide ring opening and the Friedl & auml;nder reaction, demonstrating enhanced Lewis acid activity. Additionally, the materials proved reusable, operating under solvent-free conditions, making them promising for sustainable organic synthesis and further catalytic applications.image