  Using the QUIJOTE line survey in the 32.0-50.4 GHz range, we report the
discovery of the molecule CH2CCHC4H towards the prestellar cold core TMC-1 in
the Taurus region. We also present a rigorous detection of CH2CCHC3N, along
with its detailed analysis. We identified a total of twenty rotational
transitions for each one of these molecules. The rotational quantum numbers
range from Ju=17 up to 24 and Ka<=3. The column density for CH2CCHC4H is
N=(2.2+/-0.2)x 1E12 cm-2, while for CH2CCHC3N, we derived N=(1.2+/-0.15) x 1E11
cm-2. The rotational temperature is 9.0+/-0.5 K for both species. The abundance
ratio between CH2CCHC4H and CH2CCHC3N is 18+/-4. We also compared the column
densities of these species with those of their isomers CH3C6H and CH3C5N,
derived from their J=20-19 up to J=30-29 rotational transitions observed with
the QUIJOTE line survey. The observed abundances for all these species are
reasonably well explained by state-of-the-art chemical models of TMC-1. The
observed astronomical frequencies were merged with laboratory frequencies from
the literature to derive improved spectroscopic parameters.
