CMOS image sensors (CIS) are widely used in commercial, industrial and scientific applications. The low light sensors are useful for day-through-night imaging, capturing images in extreme lighting conditions from daylight through quarter-moon darkness. The low light sensors are required for numerous applications like surveillance, security, and mobile applications. Low illumination imaging performance and dynamic range (DR) of an image sensor are limited by the temporal noise of the photodetector and readout signal chain. I will overview some of our work in the domain of low light imaging, starting from a novel pixels increasing the conversion gain and simultaneously reducing the temporal noise of the pixels to more advanced pixel architectures capable of lowering the temporal noise below sub electron level. The dual effect of increased conversion gain and reduced noise, increases the effective dynamic range in the low illumination conditions and provide an alternative to commercial low light sensors like image intensifiers, electron bombardment, EMCMOS. The use of these high responsive light sensors in applications like surveillance, security, reconnaissance UAVs, bio-luminescence and imaging systems in space platform will be discussed.