Abstract: Provided herein are novel liquid crystal based devices for the facile measurement of temperature in an MRI system. The thermometers comprise a plurality of vessels wherein each vessel contains a liquid crystal composition having a unique phase transition temperature. By scanning with appropriate techniques, the state of the liquid crystals in each vessel can be assessed, and the temperature at the time of the scan can be determined by the state of the liquid crystal compositions. Also provided are novel vessels and assemblies of vessels that can be used as MRI thermometers and which are compatible with MRI phantoms.