An algorithm for the retrieval of nighttime cloud optical and microphysical properties, based on a variation of NASA Langley's Solar infrared-Infrared-Split window Technique (SIST), has been adapted for usage by GOES-R and integrated into the Algorithm Integration Team's GOES-R processing system. This algorithm, the Nighttime Optical and Microphysical Properties (NCOMP) technique, utilizes Advanced Baseline Imager (ABI) proxy data from Spinning Enhanced Visible and Infrared Imager (SEVIRI) to derive cloud optical depth, effective particle size and liquid/ice water content. Validation of NCOMP results has yielded comparisons that meet the GOES-R program accuracy and precision specifications, yet efforts to extend and improve these comparisons and the algorithm are ongoing. This paper will present those validations and discuss the methods being used to improve the retrievals, including the development and application of a new technique that uses thermal-only wavelengths during daylight hours, including simulated 3.9-micron imagery that has the solar component of the measured radiance removed. This application of NCOMP or SIST to daytime data allows for consistency checks across the terminator and greatly increases the validation possibilities when used as simulated nighttime datasets, including the ability to compare to other daytime satellite-based retrievals that are normally derived only with the assistance of non-thermal channels, including NASA Langley's Visible Infrared Solar-infrared Split-window Technique (VISST). Additionally, more deep-dive validation opportunities are available during daytime hours when instruments in field programs and at surface sites are more apt to produce data. The application of NCOMP to data sets from both Moderate Resolution Imaging Spectroradiometer (MODIS) existing GOES platforms will also be demonstrated due to the large number of validation opportunities available outside the SEVIRI field of view.