InGaN single-quantum-well-structure (SQW) light-emitting diodes (LEDs) with an emission wavelength between violet and orange were fabricated. The maximum on-axis luminous intensity of green LEDs was 12 cd and the output power was as high as 3 mW at a forward current of 20 mA, while those of blue LEDs were 2 cd and 5 mW, respectively. The peak wavelength and the full width at half-maximum of the green LEDs were 525 nm and 30 nm, respectively, while those of blue LEDs were 450 nm and 20 nm, respectively. Successfully, InGaN multi-quantum-well (MQW) structure laser diodes were fabricated from III-V nitride materials for the first time. The laser consisted of a InGaN MQW, GaN optical guiding layers and AlGaN cladding layers. The observed stimulated emission was at a wavelength around 420 nm, with a threshold current of 610 mA (8.7 kA/cm2) and a threshold voltage of 21 V under pulsed current injection at room temperature. The stimulated emission also showed a strong transverse electric polarization. The beam full widths at half power for the parallel and perpendicular far-field radiation patterns were 5 and 17 degrees, respectively.