These beans are about 4 weeks old now and out of nowhere they started to die. I cannot figure out the cause and am not sure what's happening. Also I sprayed a neem oil concoction on them last week.

Tell us more:
When did the problems start?
What are the symptoms?
How have you been caring for the plants?
How old are the plants?
Do you have any other plants that are being effected?

Welcome to NGA, @Ridacho.

Where did your bean seeds come from, and what variety are they? Did the yellowing of the leaves start before or after spraying them with the Neem? There are viruses that can cause bean leaves to turn yellow, but I would have expected them to look more "mottled."

Also, where are you located? Are your beans in a spot where you have previously gardened?

Thank you for the response, my bean seeds are from a brand called valley green and they are an assortment of what they call garden beans, bush beans, and peas. And the yellowing was after the neem, though the browning was before. I am located in north Texas and no, I have not planted anything in this bed before.

The problem started about 2 weeks ago, and I thought it was a pest problem which is why I sprayed it with neem, but it did not help and instead started to brown and break in half. There are brown veins running through some leaves, while others have bright yellow spots, and others are just drying out. I have been watering them almost 3-4 times a week, more or less depending on the weather and they have been outside for 4-ish weeks, but they were germinated early February. And I have some other sprouts and they are also browning a little bit and they are kind of brittle with random spots.

Is there any likelihood that the soil your beans are growing in is contaminated with some sort of herbicide?

One thing to consider is that I've heard/read from several sources that it is not a good idea to spray neem oil where it sits all day in bright sunlight. It is best to spray on a cloudy day or at the end of the day. For some reason the sunlight and oil can cause something similar to the plant being sunburned, like if you don't harden off new plants gradually that have been raised indoors with plant lights.
I doubt this is the reason, but something to consider when spraying with neem oil in the future.
I've had Kentucky Wonder beans yellow and die like this but I never could figure it out.

@Ridacho, you should also check the pH of the soil where those bean plants are growing; it could be chlorosis caused by too high a pH.

Thank you all for your help, I will definitely test the pH levels, and no, there was no way the soil could have been contaminated with herbicide. Also, I will check up on the neem oil issue.

One more thought that I had - were your plants sown directly where they are growing, or did you by chance start them indoors and transplant them? (or maybe I'm the only one who ever does that...) If you did start them and transplant them, they might just be a little sunburned; in that case, the new growth should be green and healthy looking.

Thank you all for your help, I will definitely test the pH levels, and no, there was no way the soil could have been contaminated with herbicide. Also, I will check up on the neem oil issue.

I did transplant them but that was 4 weeks ago. I'll keep an eye on the new growth.

I did transplant them but that was 4 weeks ago. I'll keep an eye on the new growth.