In single and two-temperature non-isothermal electron plasma along with warm positive ion, warm negative ion and warm positron, propagation of non-linear ion-acoustic solitary waves are investigated under the variation of different plasma parameters. In this paper, we have studied the first, second and third order compressive non-linear solitary wave solutions along with their respective amplitudes by a very familiar approach known as ‘tanh – method’ with existence condition for solitary wave solutions. Again we are trying to compare the amplitudes between isothermal and non-isothermal two-temperature electron plasma. In addition to this, for two-temperature non-isothermal electron plasma - variation of energy connected with those amplitudes, fast and slow ion-accoustic phase velocity and profiles of Sagdeev potential for temperature variation of positive and negative ions are critically discussed. All the results obtained are represented graphically.