Hi Jithin,
I see you have already seen the example from SAPUI5 Explored. There the code is already there to implement comboBox. Can you please elaborate the issue you are facing ?
Below is the code present there-
<ComboBox showSecondaryValues="true" items="{/ProductCollection}">
<core:ListItemkey="{ProductId}"text="{Name}"additionalText="{Price} {CurrencyCode}"/>
</ComboBox>
"Here the additionalText is used to display the second column"
Regards,