Effective upconversion emission from an organic crystal of cyano-substituted oligo (p-phenylenevinylene) (CNDPASDB) based on two-photon absorption is presented. Frequency upconverted cavityless lasing, or amplified spontaneous emission, from the crystal pumped by a femtosecond laser of $800\mathrm{nm}$ was observed when the excitation energy exceeded the threshold of $1.3\mathrm{mJ}{\text{pulse}}^{-1}{\mathrm{cm}}^{-2}$ . Its polarization contrast was estimated to be $\sim 0.93$ . This large ratio is due to the unified unidirectional configuration of the molecular long axis in crystal, beneficial to the stimulated emission with a low threshold. These results indicate that the present CNDPASDB crystal has a potential for upconversion laser device application.