Modified Loomis-Wood diagram of some of the observed lines of 1-cyanonaphthalene. The abscissa corresponds to the value of the rotational constant. The ordinate is the antenna temperature, corrected for atmospheric and telescope losses, in milli Kelvin. Each box presents the QUIJOTE data for frequencies 2 B_rotJ^*, where J^* = J_u + 1/2. The red line corresponds to the synthetic spectrum computed for TMC-1 including the rotational transitions of all molecular species detected with QUIJOTE adopting for them the physical parameters derived in previous works. Features without a red line counterpart are unknown lines. The model contains the rotational lines of the two isomers of cyanonaphthalene and cyanoacenaphtylene reported in this work. The rotational transitions of 1-cyanonaphthalene correspond to the lines connected through blue lines (see text). The left blue line corresponds to the transitions harmonically related with half integer quantum numbers (K_a = 0, 1; a and b-type transitions; J_u=J^*-1/2). The other blue lines connect transitions of 1-cyanonaphthalene corresponding to K_a = 1, 2, 3 and 4 (a and b-type).