1 Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
2 Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario, Santa Fe 2000, Argentina.
3 Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.

Three new analogues of Tb-UiO-66 with various functional groups (-F, -Br, -NH₂) on the terephthalic acid linker of the metal-organic framework (MOF) are synthesized and characterized. The photoluminescent properties of these analogues, as well as Tb-UiO-66 and Tb-UiO-66-(OH)₂, are studied and correlated to the calculated energies for the triplet (T₁) states of each linker. The results show that the addition of electron withdrawing groups, such as -F and -Br, lead to higher T₁ energies, resulting in quantum yields in the range of 6-31%. The addition of electron donating groups, on the other hand, lowers the T₁ energy of the organic linker and inhibits energy transfer such that emission is not observed.