Hi! This is an insightful and relevant question. First a bit about what kinds of UV rays ozone protects us against

UVA: Longest wavelength, lowest energy. Ozone does not absorb this light.
UVB: Middle wavelength, middle energy. Ozone absorbs some of this light.
UVC: Shortest wavelength, highest energy. Ozone absorbs all/most of this light.

You may suspect that UVC is the most harmful, and you would be right. This is because UVC light has the highest energy, and living cells will suffer damage if they receive too much energy. If the ozone layer were not here to absorb this light, life could not exist like it does on earth.

Now let's talk about what ozone actually is. Ozone is simply 3 atoms of oxygen bonded together. The "ozone layer" has ozone (O₃) along with single atom and diatomic (two-atom) oxygen molecules. UV light provides energy to break apart an O₂ molecule into two O's. Those O's then combine with other O₂'s to make O₃, or ozone! We are protected from the light because the energy is used to make a chemical reaction happen.

Can we find another molecule to do this? Maybe, but it is unlikely that we could create enough of it to make a difference soon. Since the atmosphere is so large, it would take a lot of gas to absorb enough UV light to make up for what the ozone layer absorbs.

When you hear people talk about an "ozone hole," they are really talking about a place where there is less ozone. It doesn't mean that there is no ozone. There are many reasons this happens, and we have stopped using things like chlorofluorocarbons (CFC's) because of the negative effects on the ozone layer.

Here is a great article from NASA, which answers 20 common questions about the ozone layer, and also covers the chemistry of ozone and why things like CFC's cause ozone depletion:

Here is one more resource that talks about the ozone layer in relation to climate change:
ozone hole