A 1940s time capsule in the heart of one of Brisbane's most popular suburbs has sold for $2.35 million.

The unrenovated, pre-war duplex had been held by three siblings for the past 45 years before selling to a local family, who plan to turn it into their 'forever home'.

Selling agent Peter Hutton of Hutton & Hutton Real Estate said the four-bedroom, two-bathroom property at 5-7 Mark St, New Farm, had generated a lot of interest and attracted three offers.

But he admitted many prospective buyers found it hard to envisage what to do with the property, given its pre-demolition status and the fact it had a brick wall down the middle of the house.

"It was purpose-built as a duplex, so basically two apartments side-by-side with a brick wall down the middle," Mr Hutton said.

"For most buyers that was a hard intersection of pre-war and not being a typical colonial, so most buyers couldn't kick in their imagination to work out what to do with it."

That was until the lucky buyer brought an architect along with them one day.

"The architect gave them the level of confidence they needed and they submitted an offer," Mr Hutton said.

"All of a sudden, two other parties also submitted offers, so we had three contracts on the one day.

"The end buyer had the best terms and conditions, so we went with them - it was a really good outcome."

Mr Hutton said the buyer had been looking for a place to call home in New Farm for a long time.

The vendors of 5-7 Mark St also recently sold the adjoining, century-old property at 22 Abbott Street for $3.36 million at auction to a local family who plan to renovate.

According to property researcher CoreLogic, the sale of 5-7 Mark St was the top sale in Queensland in the past week.

New Farm is a high demand suburb with a median house price of $1.7 million.