In this work, two different contact imaging systems were designed, fabricated and tested. The first system was designed to allow continuous, non-invasive imaging of calcium changes in multiple neurons. This is particularly important for studying brain functionality. First, emission filter for the system was designed, fabricated and tested. The filter used polyvinyl as a chromophore for UV light attenuation and polyvinyl acetate (PVAc) as a chromophore holder. The neurons were loaded with Fura-2 AM, a calcium sensitive fluorescent dye, which has dual excitation wavelengths at 340 nm and 380 nm with ratiometric emission at ~510 nm. Measurements with the PVAc based benzophenone-8 (PVACB-8) filter revealed an attenuation of approximately two and a half orders of magnitude, which was sufficient to collect fluorescence signal from Fura-2 AM loaded neurons. The PVAcB-8 filter was compared with a commercially available dichroic filter and proven more efficient in fluorescent imaging. The developed PVAcB-8 filter was used in the design, fabrication and verification of a novel complementary metal oxide semiconductor (CMOS) imager based miniature lensless contact imaging system. The device consisted of a removable, absorption filter interfaced with a CMOS imaging sensor and an external DG-4 lamp for excitation. The system was used to acquire fluorescent images from live neurons by monitoring calcium changes with Fura-2 AM dye. Fura-2 AM loaded Lymnaea stagnalis neurons were stimulated with dual excitation wavelengths of 340 nm and 380 nm; the image sensor detected 510 nm emission. It was shown that the system was capable of detecting intracellular calcium changes in Fura-2 loaded neurons. Further, this sensor also enabled viewing of multiple neurons over a large surface area simultaneously, an option that is not readily available in conventional light microscopy. The second system was designed to allow continuous, monitoring of chlorophyll and colored dissolved organic matter (CDOM) in an aquatic environment. A continuous assessment of these two water quality parameters can be used for determining the health of a body of water, in anticipation and a possible prevention of harmful phenomena. Design, fabrication and verification of a proof-of-concept miniature fluorometer, for continuous assessment of two parameters for water quality are presented here. The fluorometer system utilized light emitting diodes (LEDs) for fluorescence excitation and absorption filters, for excitation light attenuation. Excitation LED for Chlrorophyll had peak emission at 465nm and excitation LED for colored dissolved organic matter (CDOM) had peak emission at 341nm. The prototype device demonstrates the concept of attaching two different absorption filters, onto a single sensor array, for measuring fluorescence signals from two different fluorescent dyes. The system’s abilities to detect fluorescence from various concentrations of fluorescein as a close simulant and calibration standard for Chlrorophyll; and Quinine sulfate dihydrate (QSD) as a simulant and calibration standard for CDOM were tested. Fluorescent signal for fluorescein between 0.7 nM to 1000 nM and QSD between 2 ppb to 500 ppb was successfully acquired. Both systems demonstrate alternative approach to fluorescent imaging. The field of view in a contact imaging system is defined by the size of the pixel array and can be over 1cm2. The light collection efficiency (LCE) can be as high as 50%, and unlike in a conventional microscope there is no tradeoff between the field of view and the LCE. The pixel array area can be used for a single fluorescent application or divided into multiple sub sections for multiple fluorophores. The proof of concept designs presented in this thesis demonstrate that contact imaging systems are capable to compete against the existing systems and may replace them in the future.