Quick answer: no — Connecticut does not let a surviving spouse add a deceased spouse's unused exemption to their own. Run your own numbers in the Connecticut estate tax calculator.
One exemption per spouse, confirmed directly
A Connecticut-only QTIP election
Conn. Gen. Stat. §12-391(f) lets an executor elect the qualifying income interest for a surviving spouse under IRC section 2056(b)(7) for Connecticut purposes only, regardless of whether the same election is made on the federal return. Property for which this Connecticut-only election is made is included in the decedent's gross estate as if the election had been made federally too, giving planners a genuine tool independent of what happens on the federal side.
Less critical now that the exemptions match
For deaths on or after January 1, 2023, where the Connecticut and federal exemptions are identical, this state-only technique matters less than it once did. But it remains genuinely useful for estates that were planned during the years when the two figures diverged, and as a hedge in case Connecticut's exemption and the federal one drift apart again under future legislation.
Bypass trust planning is still the standard workaround
Because there's no portability, Connecticut couples typically rely on a credit shelter (bypass) trust to make sure each spouse's own exemption actually gets used at the first death, rather than passing everything outright to the survivor and risking one exemption going to waste entirely.
A local probate attorney can review your estate — many offer a free consultation.
This planning question is separate from Connecticut's own gift tax — see the threshold and rates guide for how the shared $15,000,000 estate-and-gift-tax cap works.