Recently, we have demonstrated optically-pumped edge-emitting organic laser devices consisting of a Alq3:DCM film (5% DCM) deposited onto a polished GaAs(100) substrate coated with an 1-μm-thick layer of RF sputtered SiO2 using a cleaving method. The threshold density was typically 3 μJ/cm2 in a sample with a cavity length of 5 mm. The internal loss α and the gain coefficient β were found to be about 10.5 cm -1 and 3.2 cm· μ J-1, respectively. BSB-Cz has quite-high efficiency as blue laser material. In this work, organic laser devices based on CBP:BSB-Cz films (6% BSB-Cz) were vacuum-deposited onto polished GaAs(100) substrates coated with an 1 μm-thick layer of RF sputtered SiO2. The cleaved samples were optically pumped by a N2 gas laser (wavelength: 337 nm) with a pulse width of 600 ps at a repetition rate of 20 Hz. We investigated the emission spectra, the emission intensity and the full width at half maximum (FWHM) by varying the excitation intensity. Pumping a sample with a resonator-length of 5 mm, the emission intensity was found to drastically increase at certain. The FWHM drastically narrowed as the emission intensity rapidly increased. The threshold density was 0.48 μ J/cm 2 for a resonator length of 5 mm. The internal loss α and the gain coefficient β were found to be about 3.1 cm-1 and 17.4 cm· μ J-1. We found that BSB-Cz is a higher efficiency lasing material than Alq3:DCM. The polarization characteristics and the relationship between threshold density and resonator length were also investigated.