THE CZTI INSTRUMENT ABOARD ASTROSAT MEASURES THE DEGREE OF POLARIZATION OF GAMMA-RAY BURSTS (GRBS) IN A NARROW ENERGY RANGE (100-300 KEV). SPECTRAL INFORMATION WHICH IS A CRUCIAL COMPONENT IN DETERMINING THE SOURCE OF POLARIZATION IS READILY PROVED BY FERMI GBM. POLARIZATION DATA WITHOUT SPECTRAL INFORMATION CANNOT DISCRIMINATE BETWEEN MODELS. WE PROPOSE TO DISTINGUISH BETWEEN PROMPT EMISSION POLARIZATION MODELS BASED ON THE POLARIZATION DATA AVAILABLE FROM ASTROSAT TOGETHER WITH SPECTRAL MEASUREMENTS BY FERMI GBM UNDERLINING THE COMPLEMENTARY NATURE OF THIS PROJECT. WE DEMONSTRATE THE FEASIBILITY OF OUR METHOD THROUGH GRB 160802A WITH JOINT ASTROSAT-GBM OBSERVATIONS.