- Calculate your DBEs (double bond equivalents):
\[\mathrm{DBE} = \frac{2c-h+2}{2} = \frac{2\cdot 11 - 14 +2}{2} = 5\] Note that a benzene has 4 DBEs!
- Shifts at 7.5 ands 7.4 are definitely not alkine protons. Aromatic protons are more likely, aren't they?
- Largest couplings between benzene protons are typically ortho couplings. How large are they in your case?
- Two sets of doublets at 7.5 and 7.4 ppm might indicate a 1,4-disubstituted benzene. You might want to play with some increment rules here.