1 Supporting information of Synthetic Iron Porphyrins for Probing the Differences in Electronic Structures of Heme a 3 , Heme d and Heme d 1 Sk Amanullah, Paramita Saha, Rajat Saha, Abhishek Dey* Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata, India 700032 Email: abbeyde@gmail.com Table of content Synthetic Characterization data…………………………………… Page 2-17 Structural comparison between Fe II TPC-Im2 and Fe II TPP-Im2……... Page 18 ORTEP diagram of the complexes………………………………. Page 18-19 Short contact interactions in the crystals………………………… Page 20-21 Characterization data for CO complexes…………………………..... Page 22 Characterization data for NO complexes……………………………. Page 23 The g-values and the A values of the Fe II - 14 NO complexes………… Page 24 Simulated EPR data corresponding to Fe II - 14 NO complexes………... Page 25 Relative MO diagram of complexes……………………………... Page 26-27 DFT optimized coordinates of the complexes…………………… Page 27-66