Single crystals of two new charge-transfer compounds, anthracene-F₄TCNQ and tetracene-F₄TCNQ, were grown by physical vapor transport. Both of these crystals have a 1 : 1 donor : acceptor stoichiometry and mixed stacking structure. The charge-transfer degrees at room temperature are estimated to be 0.051–0.089e and 0.086–0.148e for anthracene-F₄TCNQ and tetracene-F₄TCNQ, respectively. The CN stretching frequency depends linearly on the charge-transfer degree. A single-crystal field-effect transistor made from tetracene-F₄TCNQ has average and maximum mobilities of ∼10⁻⁴ cm² V⁻¹ s⁻¹ and 0.006 cm² V⁻¹ s⁻¹, respectively, and an on/off ratio of ∼10⁵. The tetracene-F₄TCNQ charge-transfer single crystals exhibit good photoresponse and on–off switching.