Yes, you can probably insure 2 different cars that are registered or titled under your name with 2 different auto insurers, each one thus insured by a different insurance company. However unless there is a good reason to do so it would likely cost you more to insure you cars this way. There are some state laws and carrier regulations that will not allow this, because of the liability implications.
Insurance companies often grant a 'multi-car' discount to policies that have more than one vehicle on them. This multi-car discount may apply only to the coverages that apply to both vehicles.
Also, many insurance companies rate the highest risk driver with the highest risk vehicle. So if you create two policies, not only are you denying the multi-car discount, but you may also create a situation where the highest risk driver is rated against both vehicles (instead of being rated against just one vehicle).
It may be necessarily in some situations to insure your cars with 2 different carriers, such as one is an older collectible car that can only obtain specialized insurance and one car is a newer daily commuter car that you would get better insurance rates with a normal insurance company.
To see if we can help you get the insurance you need on one or both of your vehicles, click here for a car insurance quote.