Far-field and nearfield acoustic measurements have been conducted on equal and unequal twin circular slot jet for different spacing ratios. The twin jets were operated at high, moderate and low levels of underexpanded flow conditions. Measurement of acoustic power index, OASPL, spectra and shock-cell visualization have been carried out to evaluate equal and unequal twin jets. The results indicate that unequal twin jets are efficient screech tone suppressors at high and moderate levels of underexpanded flow conditions but are ineffective at lower levels of underexpansion. The cross correlation studies reveal an antisymmetric coupling for moderately underexpanded equal twin jet and symmetric coupling for low levels of underexpanded unequal twin jet. © 2015 Elsevier Ltd.