The Arizona Radio Observatory (ARO) operates two radio telescopes in the millimeter and sub-millimeter wavelength region. Recently, one of these instruemnts, the aging, former NRAO 12 meter telescope on Kitt Peak, was replaced with one of the 12 m ALMA prototype antennas. The high performance design of this new instrument, including its 20 microns surface and sub-arcsecond pointing, will expand observational capabilites at the ARO. New receivers and backends are also in development at ARO. A dual polarization sideband separating SIS mixer covering the 0.7 mm atmospheric windw, ranging from 385 GHz to 500 GHz, has been installed as a facility instrument on the Sub-Millimeter Telescope (SMT) on Mount Graham. A prototype Band 2 receiever, based on HEMT amplifier technology, has been built and tested on the sky. These new additions and other developments will be presented.