Tuning the structural and electronic properties of novel thiophene-pyrrole based 1,2,3,4-tetrazine Rakesh Dutta and Dhruba Jyoti Kalita Eur. Phys. J. D, 71 4 (2017) 87 Published online: 11 April 2017 DOI: 10.1140/epjd/e2017-70724-7