The structural, optical and electrical properties of dilute nitride p-n junction GaP1-x-yAsyNx structures grown on n-type GaP (100) and n-type Si (100) misoriented by 4A degrees towards the  direction substrates were studied. These properties of the samples, which were grown by using molecular beam epitaxy (MBE) technique, were investigated by using high-resolution X-Ray diffraction (HRXRD), energy dispersive X-Ray (EDX), room temperature photoluminescence (PL) and current-voltage (I-V) measurements. Both alloy composition values (x, y) and crystal structure parameters were determined from HRXRD measurements while the band gap energies were obtained from PL measurements. Composition values were also determined by using EDX measurements and compared with HRXRD results. The better crystal quality was found for the sample grown on GaP substrate from both the HRXRD and PL results. In addition, the theoretical band gap energies calculated from the band anticrossing (BAC) model and experimental band gap energies determined from the PL measurements were compared and found to be in good agreement with each other. The p-n junction GaP1-x-yAsyNx/GaP (Si) diode devices were fabricated to investigate their electrical properties. The I-V characteristics of diodes were analyzed at room temperature and the diode formed on GaP substrate exhibited better results compared to other diode.