Its very easy to Import records of an entity with 1:N relationship to different entity. But OOB there is no such tool/wizard to create a N:N relationship between the records of two different entities.
Today I had a requirement to upload the entities record with N:N relationship in a new CRM 2011 deployment. A very special thanks to CRM-MVP Andrii for creating a wonderful tool for this act and making the N:N import so easy.
The Solution can be downloaded from Codeplex. Simply Import the managed solution in CRM , publish the customization and try the N to N Import/Export.
The Import file needs to be in a .CSV format (semicolon delimited) with Unicode Encoding. Kindly follow my Previous_Blog to achieve the same file format for Data Import.
After following the steps properly if you see the following screen with the Blue line bar without any errors, the import has been completed successfully.