The kinetic inductance detector (KID) offers simple fabrication, intrinsic multiplexing of thousands of detectors per cable, much higher dynamic range than competing technologies, and near background-limited operation at mm and submm-wavelength frequencies. I'll discuss two related applications. The first, SuperSpec, is an compact, mm-wavelength, on-chip spectrometer. Its small size, wide spectral bandwidth, and highly multiplexed detector readout will enable construction of powerful multi-object spectrometers for high-redshift observations. The design employs a filter bank consisting of a series of superconducting thin film circuit elements, each coupled to titanium nitride lumped-element KID. I will discuss the design, optimization, and measured performance of prototype devices and the upcoming observing run of the SuperSpec demonstration instrument. The second project, the Chicago CMB-KIDs program, is a lab demonstration of a KID-based, polarization sensitive, multi-band array optimized for CMB observations. I'll discuss our pixel designs and current progress toward demonstrating a full-scale array suitable for deployment in the Stage-4 CMB experiment.