Résumé : “Photochemical synthesis of polycyclic aromatic hydrocarbons and NMR‐1H study of bay protons. Specific solvent effects and nuclear Overhauser effects”. Dinaphtho[1,2‐a 2′,1′‐j]anthracene (4a), 9‐bromo‐dinaphto [1,2‐a; 2′,1′‐j]anthracene (4b), 9‐methyldinaphtho[1,2‐a; 2′,1′‐j]anthracene (4c), benzo [c]naphtho [2,1‐1]chrysene (7), benzo [a]naphtho [2,1‐j]anthracene (3), naphtho [2,1‐c]chrysene (9) and dibenzo [c,1] chrysene (12) have been synthesized by the photocyclodehydrogenation of 1,2‐diarylethylenes (5,8) and bis (arylvinyl)arenes (6, 10). The NMR study has been mainly focused on the bay protons involved in specific solvent effects (Table 4) and nuclear Overhauser effects (Table 5). Copyright © 1983 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim