The interaction of methanol with terthiophene (as a model of polythiophene, denoted hear as 3PT) was investigated by using density functional theory (DFT) at BLYP-D3/6-31+G(d,p) level of theory . The computed density of states (DOS) points to notable orbital hybridization upon interaction of methanol with 3PT. Natural population analysis (NPA) was used to find out the charge distribution as well as the net charge transfer of 3PT-methanol system to assess the sensing ability of terthiophene. The computed dipole moment reveals that the amount of the dielectric µD was changed upon interaction of methanol with 3PT. On the basis of calculated changes in the HOMO-LUMO energy gap it can be found that the electronic property of 3PT is sensitive to the interaction of methanol. After fully energy relaxation, the interaction energy value of methanol with 3PT at the most stable configuration was calculated to be -16.4 (-13.5 counterpoise corrected energy) kJ mol−1 which is a proof for physisorption of methanol.