Synthesis, characterization and its humidity sensor application of Poly(methyl orange) (PMO) was done under inert atmosphere. In order to increase the molecular weight and processability it was block copolymerized with ε- caprolactone (CL) and tetrahydrofuran (THF) separately. The conductivity value of PMO was found to be decreased after the chemical conjugation with poly(ε-caprolctone) (PCL) and poly(tetrahydrofuran) (PTHF) blocks. Thus obtained triblock copolymer was subjected to humidity sensor application and the results are critically compared. The triblocks were further characterized by fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, Fluorescence spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), field emission scanning electron microscopy (FESEM) and cyclic voltammetry (CV).