In applying porous Si (PS) to color display technology, it is important to fabricate light emitting devices with three primary colors. However, there have been few reports on blue and green electroluminescence (EL), and its mechanism (even the relationship between PL and EL spectra) is unclear. To obtain blue and green EL and to investigate its mechanism, we have formed PS anodized under UV illumination (UV-PS) with green photoluminescence (PL) and porous SiC with blue PL. Consequently, green and blue light emitting devices were successfully fabricated by using these materials. The observed spectra are from 350 to 750 nm with a peak of, 520 nm for ITO / UV-PS junctions and from 300 to 600 nm with a peak of 470 nm for ITO / porous SiC junctions. The EL mechanism is also discussed by reference to experimental results of comparing PL and EL spectra and of investigating the dependence of EL intensity on current.