"did think of" is correct and usable in written English.
You can use it as the past tense of the verb "think." For example, "I did think of inviting them to my party, but I decided against it."
"Twice I even did think of resigning," she said, "but I was always thinking of how to survive and earn money and there are not so many papers in Serbia".
I did think of them, but I didn't.
"I did think of them later," she says.
Le Corbusier did think of nature and landscape, in his way.
"He did think of organization first, foremost and only," Dungy said.
I did think of her as my equal in every respect.
"We did think of putting a sort of wrapper around the pictures".
If I did, think of this entry as a 1980s style 12" remix.
The 120,000 citizens of Mostar did think of themselves as a single community, sharing a city and a bridge.
We did think of a sign, but we decided the message we'd come up with was too crude.
Ms. Goskowski really did think of her trip to Nazareth and Martin as something, well, related to the soul.
