Can I track a stolen iPhone using the IMEI?

Sorry, no. Only your carriers have the capabilities of tracking your iPhone with the IMEI number, but they will typically only do so with a court order to assist in an emergency such as a missing person. The only way you can track your lost iPhone is by using the Find My application, if it was setup beforehand.

Please review the following Support Articles:

Find your lost iPhone or iPad - Apple Support

If your iPhone or iPad was stolen - Apple Support

No.

There is no mechanism by which you can track an iPhone using an IMEI.

Only mobile carriers can do that, and usually will only do so if they receive a court order and in case of a missing person.

No. But you can use "Find my..."