No, the Estimated Tax payments you are making are for your personal return and therefore not a business expense.

For you to deduct the convenience fee you would have to pay something directly for your business, when it comes to paying your Estimated Payments that is not directly a business expense.

Taking Business Tax Deductions

@markdu5

My apologies for asking the same question twice.  I couldn't find the question again the first time, and I even seem to have 2 different profiles now.  My question is here

https://ttlc.intuit.com/community/tax-credits-deductions/discussion/deduct-credit-card-convenience-f...

and here

https://ttlc.intuit.com/community/business-taxes/discussion/re-if-my-business-goes-on-a-schedule-c-o...

and I got two opposite answers.  I'm not sure how to proceed.

Yes you did receive two contradictory answers.  Diane is correct in stating that you can only deduct fees that are used for business transactions. You cannot deduct the convenience fees used to pay estimated taxes.