Lutron made dimmers for URC in the past.  They are discontinued now.  You can still pick them up cheap from ebay.  they are controlled via RF from URC remotes directly or through an RFTX1 adapter if you want to control them via MRX2 with the mobile app.

Just be sure you order the proper version.  There is an "MRF-A" version if you have a standard 418Mhz remote, and an "MRF-B" for the i-series 433MHz remotes.


edit to add:  These dimmers don't play nice with LED lights.  They need at least a 40 watt load to dim properly.