In this study, theoretical analysis on the geometries and electronic properties of various conjugated (phosphaalkene)s is reported in order to investigate the influence of the incorporation of phosphorus atom into the backbone of the compound. The theoretical ground-state geometry and electronic structure of the studied (pphenylenephosphaalkene) s (PPP) are optimized by the hybrid density functional theory (DFT) method at the B3LYP level of theory with 6-31G basis set and compared with those of (p-phenylenevinylene) (PPV) and (p-phenylene nitrilomethylidyne) (PPN) and finally relate this values with synthetic Mesityl of phosphaalkene (DMPPP). The effects of the phosphorus atom and substituent incorporation on the geometries and electronic properties of the materials were discussed. The results of the of the study indicate how the electronic properties can be tuned by heavy phosphorus incorporation and side group substituent and suggests that organophosphorus compounds as good candidate for optoelectronic applications.