Don't toss them. some of the leaves got a bit chilly (and froze), but the growing tips look ok :)

Linda

40s didn't do that. It was a freeze. As noted, they're not goners.

According to Weather Underground, the lowest temperature reached in my area in the last 24 hours was 43 degrees F (and it's been drizzly). We had one cold day today in a week of 70s and sunny otherwise. I was hardening off the basil all week and didn't think to move it back inside during the freak cold snap.

It doesn't take a frost to do that kind of damage to basil. It is a very sensitive crop. You could wait to see a recovery but replacement plants are a more logical solution. I sold 30 potted basil plants today at a farmers' market and all plants could have the tops pinched out and lateral branches at a lower node would replace the top in 10 days. Your plants appear to have lost lower leaves and show no later branching. That is not a good sign.

Yes, I guess that's true. Basil won't be killed by temps in the 40s, but blackened leaves are often the result.