You report all your income and file a resident tax return in Massachusetts and a nonresident tax return in Connecticut.
In general, the nonresident's state of residence will allow a credit for the income taxes paid to Connecticut for income earned in Connecticut. The nonresident who works in Connecticut will be required to file a nonresident return (Form CT-1040NR/PY) in Connecticut as well as a resident income tax return in his state of residence.
Please see the following: https://portal.ct.gov/DRS/Individuals/Individual-Tax-Page/Nonresident-Working-in-Connecticut#:~:text...
Also, for more general information please see: https://turbotax.intuit.com/tax-tips/state-taxes/multiple-states-figuring-whats-owed-when-you-live-a...
Answers are correct to the best of my ability but do not constitute legal or tax advice.
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