We report on optically pumped lasing from a vapor-grown crystal of thiophene/phenylene co-oligomer, 2,5-bis(4′-methoxybiphenyl-4-yl)thiophene (BP1T-OMe). By using a pair of parallel facets of a thin sword-like crystal as a Fabry–Pérot resonator, laser oscillations were obtained in the 0-2 emission wavelength at room temperature. Time decay profiles of the lasing band revealed a pulse-shaped emission with delay time of 50 ps. Excitation wavelength dependence of the PL spectra exhibited Raman scattering peaks in particular stimulated in the 0-2 emission band under off-resonant excitation. These light amplification properties were discussed in term of the crystal dimension and H-aggregate structure in the vapor-grown BP1T-OMe crystal.