This extention customizes the default coupon genration functionality of the opencart and provides a hybrid version of the extention by not changing any core files.Kindly find the below features of the extention
Features:
1) Bulk coupon genration: Create multiple coupons at same time
2) Single coupon can provide different discount to different product or categories
3) No core files changed
4) All the default functionality of opencart left intact

Pro Version:
* Export Report of all Coupon details
* Export Report of all Coupons used history
* Import Coupon through csv file
Open below link to download
URL://http://www.opencart.com/index.php?route=extension/extension/info&token=83eb17093f8a29c3586a2c11a864815d&extension_id=27108

Steps to install:
1) Vqmod is required.
2) Copy the xml file in the vqmod->Xml folder
3) New module features can be find in the default coupon extention of opencart.