The performance of thermoelectric material is quantified by the figure of merit (ZT). Recent advances have shown that it may be possible to increase ZT of some materials via the dilution of another element with strong electro-negativity, whose impurity levels can lead to drastic increase in the density of states of the host material. One such material system is the “dilute nitride”, which consists of III-V semiconductors, such as GaAs or GaP, which has been lightly alloyed with N. Compared to GaAs, the GaAs1-xNx may have significantly different band structure with a noticeable peak in the density of states. Overall, it was predicted that the inclusion of N should leads to increased effective mass of the density of states, which should then leads to increased Seebeck coefficient (S) and, if the electrical resistivity and thermal conductivity is unchanged, an increase in the ZT as well. Hence, we have sought to investigate the relationship between the atomic percentage of N (N%) and the Seebeck coefficient of GaAs1-xNx. Specifically, we explored the variation of N content in GaAs1-xNx in the range of 0.5% to 1.5%, which, to our knowledge, has not yet been investigated. The thin film GaAs1-xNx (~200 nm thick) was grown by a Gas-Source Molecular Beam Epitaxy on semi-insulating GaAs substrate. Since the Seebeck coefficient also depends on the carrier concentration as well, our samples were grown over a range of N% (0.5-1.5%), but approximately the same concentration (~4.6E17 cm-3). The characterization of the materials, which includes the measurement of the resistivity, carrier concentration, mobility, and Seebeck coefficient, was achieved via circuitry that is directly fabricated onto the material via standard photolithography techniques. Our results, in addition to confirming a previously-observed trend that S decreases with small amounts (~ 0.4 atomic %) of added Nitrogen also exhibits new behavior. It was observed that the S shows a minimum around 1% N and then increases at higher N concentrations. This decrease in S at low N% could be due to a reduction in bandgap and the effective mass, while the increase in S at higher N% could be explained by the overlapping of multiple conduction bands, both of which could be predicted through the k.p theory.