You can file a federal tax return reporting less than the minimum taxable income required to file. So if you only have a few dollars of dividend income, a tax return can still be filed.
You also know that as a US citizen you are required to report All of your worldwide income on federal tax return, both US sourced income and all foreign sourced income.
IRS Publication 54 Tax Guide for U.S. Citizens and Resident Aliens Abroad - https://www.irs.gov/pub/irs-pdf/p54.pdf
