Doing the right thing could come with a writeoff.

Reps. Hakeem Jeffries (D-Brooklyn) and Pete King (R-L.I.) proposed legislation Tuesday to extend the tax deduction period for anyone contributing to the families of two slain city cops.

“Whenever tragedy occurs, it’s important for representatives of the community to step up and do the right thing,” said Jeffries. “Police officers’ lives matter. Civilians’ lives matter.”

The bipartisan legislation would allow anyone donating to help the families of slain Officer Wenjian Liu and Officer Rafael Ramos through April 15 to deduct the money from their 2014 return.

The two congressman dubbed their bill the “Slain Officer Family Support Act of 2015.”

The cops, described by Jeffries as “American heroes,” were gunned down by a killer who came north from Baltimore looking to kill city police officers.

“As tragic as it was, those murders brought the city together and highlighted how vital the police are,” said King. “In times like that, it’s important for the government to reward good behavior.”