Fast microfluidic mixers are a valuable tool for studying non-equilibrium processes in solution at the microsecond time scale. But microfluidic mixers that are compatible with infrared (IR) spectroscopy have seen only limited development due to poor IR transparency of the conventional microfabrication material. This thesis describes the design, fabrication, and characterization of IR transparent calcium fluoride-based continuous flow mixers capable of measuring kinetics with micro-millisecond time resolution with IR spectroscopy, when integrated into an IR microscope. Our fabrication methodology leverages advancements in the nanofabrication and 3D-printing technologies. Microfluidic channels are directly fabricated on calcium fluoride substrates through photolithography and bonded to another drilled window via a heated press, effectively sealing the channel. This sandwiched calcium fluoride assembly is then enclosed within a 3D-printed flow cell, providing tubing connections for continuous flow applications. This continuous flow cell allows the mapping of time delays onto distances within an observation channel, with time resolution and the observable time window determined by factors such as flow rate, the size of the IR observation beam, and channel dimensions. Incorporating various "zig-zag" serpentine-based mixer design, we achieved homogeneous mixing at a flow rate of ranging from 0.4 to 0.7 mL/min. Kinetic measurements involving a model reduction reaction of ferricyanide by ascorbic acid demonstrate the capability to resolve relaxation processes occurring within one millisecond using a glowbar IR source and hundreds of microseconds using a laser IR source. This work opens doors for the investigation of various intriguing biomolecular systems, including DNA hybridization and protein folding, among others.