Can we write some validation on the contact role insert?

Hi Rajesh,

We cannot add any validation on the contact role. Even trigger does not work on the Account contact role.
But there are ways to achieve the Opportunity Contact Role, may be this can help you :-
1. Simply remove the [New Opportunity] button from the Opportunity Related List on the Account Page Layout. This will push your users to click on the Contact to create the Opportunity which will automatically make that Contact the Primary Contact on the Opportunity.
2. There are free App's on the AppExchange that you can download.
1. https://appexchange.salesforce.com/listingDetail?listingId=a0N300000016cbDEAQ
2. https://appexchange.salesforce.com/listingDetail?listingId=a0N300000025Vs1EAE