Over the last few decades, extensive research is carrying out to encounter the cooling demand of high heat flux electronic instruments. Among the emerging cooling technologies, synthetic jet (SJ) proved to be an efficient and a compact candidate to meet the cooling demand of future electronics. SJ actuator is basically a novel Zero-net-mass-flux (ZNMF) device which allows momentum transport to the ejected fluid without any net mass transfer over an actuation cycle. The design of the orifice in SJ plays a significant role in the behavior of the ejected fluid from the orifice. Hence, the thermal performance of the SJ is found to be altered with the change in the orifice shapes. Here an experimental investigation of sharp-edged (diverging) orifices SJ has been carried out for half-opening angle of 30°, 45° and 60° having the same throat diameter equivalent to the circular orifice (d =15 mm). Experiments are performed at constant Reynold number, Re = 4062 by operating the acoustic actuator at 4 V_rms and 40 Hz. Results show that sharp-edged orifice with an half-opening angle of 30° and 45° provide an enhancement in heat transfer in comparison with circular orifice. Also, for higher surface spacing (z/d > 10), all the tested cases of diverging orifice exhibit higher thermal efficacy than the round orifice.