Role of Coupler to Design Organic Magnetic Molecules: LUMO Plays an Important Role in Magnetic Exchange Suranjan Shil, Moumita Roy and Anirban Misra * Department of Chemistry, University of North Bengal, Raja Rammohunpur, Darjeeling 734013, West Bengal, India Phone: +919434228745; Email: anirbanmisra@yahoo.com Table S1 UB3LYP Level Absolute Energies in a.u., and Intramolecular Exchange-Coupling 〈 2 〉 Constant (J cm -1 ) Using 6-31+G(d) Basis Set, for the Diradicals (1–7) Diradical Triplet BS J(cm -1 ) E −1606.00764 −1606.00742 1 〈 2 〉 2.14 1.12 47.33 E −1606.01601 −1606.01590 A 2 〈 2 〉 2.13 1.12 18.03 E −1759.64745 −1759.64715 3 〈 2 〉 2.17 1.13 63.31 E −1759.66004 −1759.65996 4 〈 2 〉 2.13 1.12 17.38 E −1759.66331 −1759.6623 5 〈 2 〉 2.12 1.12 17.56 E −1759.66342 −1759.66336 6 〈 2 〉 2.12 1.12 13.16 E −1759.65373 −1759.65365 B 7 〈 2 〉 2.12 1.12 13.04 Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2015