The current paper communicates the thermodynamic investigation on non-recuperated organic Rankine cycle system employing environmentally friendly mixtures of hexane/pentane, isohexane/pentane, and butane/pentane. Results indicate that thermodynamic performance of a system employing referred mixture is superior, whereas system's economy is inferior to employing pure working substance. Furthermore, a multi-objective optimization is carried out to obtain optimal system performance. It is observed that the exergetic efficiency and UA(tot) value obtained through a number of iterations are 44.79-52.81% and (3.2 -9.12) x 10(4) W/K, respectively.