Circumtrindene as a pi-bowl shaped carbon structure decorated by Li and Li+ and examined for H-2 adsorption using M06-2X/6-311++G(d,p)//B3LYP/GEN level of theory. All polygons, bonds and various carbon types, in concave and convex sides, were examined to find the best location for Li and Li+. ZPE and BSSE-corrected interaction energy values were calculated for connection of Li or Li+ to circumtrindene and for connection of H-2 to Li C36H12 or Li+-C36H12. Better understanding of the adsorption properties were achieved by DOS, PDOS, OPDOS diagrams and NBO analysis. Results showed that in Li C36H12 and Li+ C36H12 complexes, the concave side has more binding energy than the convex ones and Li+ C36H12 has more binding energy than Li C36H12. Also, for Li C36H12, when Li was in center polygon and concave side and for Li+-C36H12, when Li+ was in 6-2 polygon and convex side, the highest interaction energy were obtained. For H-2 adsorption, the complexes contain Li and Li+ in center polygon and concave face have the highest binding energy, equal to 15.72 and 16.29 kcal mol(-1) respectively. Binding energy values indicated that adsorption of Li or Li+ onto C36H12 and adsorption of H-2 onto Li C36H12 or Li+-C36H12 in all positions are chemisorptions, but the connections are not so strong for H-2 molecules. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.