Chemical Bath Deposition (CBD) is an aqueous analogue to Chemical Vapor Deposition. It has been used primarily in the process of fabricating Cu(In,Ga)Se2 and CdTe based thin film photovoltaics. Its low temperature nature makes it an attractive technique for fabricating semiconductor devices on polymeric substrates. But a major drawback of batch CBD is the formation of particles which generates a lot of waste and creates defects in devices. Moreover, it is necessary to better understand the role of particle formation and deposition in CBD thin film growth process. We have developed a continuous flow microreactor for CBD. This novel reactor provides the capability to control the homogeneous chemistry before impinging on the substrate thus help us in differentiating the molecule-by-molecule growth from the cluster-by-cluster growth. In this talk, our recent progress in studying the reaction kinetics of CBD CdS using this microreactor will be presented.