The reference material was prepared following the original literature by Volkringer et al. , which synthesis was then varied to achieve a different particle shape. The optimized modulated MIL-116(Ga) synthesis protocol is as follows: Ga(NO 3 ) 3 xH 2 O (2.4 g, 9.4 mmol) was dissolved in 20 mL of de-ionized water (DI water) and stirred. Then, mellitic acid (1.198 g, 3.50 mmol) was added and stirred until fully dissolved. Sodium formate (0.81612 g, 12 mmol) was dissolved in 10 mL of DI water. The two solutions were mixed, stirred for another 5-10 minutes and transferred to a Teflon-lined autoclave. The autoclave was sealed and heated at 210 °C for 24 hours in a furnace. White crystalline particles were collected by centrifugation at 9000 rpm for 10 minutes, washed thrice with DI water and dried at 40 °C for 24 hours. The same procedure was followed using different amounts of HCOONa (see Figure ). Different modulators were tried to manipulate the particle morphology of MIL-116(Ga). For more experimental details, please refer to Table -S2 in the supporting Information.