The reactions of L 1–3 Li salts containing different Y,C,Y-chelating ligands L 1 =2,6-(t-BuOCH 2 ) 2 C 6 H3-1, L 2 =2,6-(MesOCH 2 ) 2 C 6 H3-1 and L 3 =2,6-(Me 2 NCH 2 ) 2 C 6 H3-1 with PCl 3 is reported. While the presence of ligands L 2,3 afforded the synthesis of dichlorophosphines L 2 PCl 2 (2) and L 3 PCl 2 (3), the use of ligand L 1 resulted to the isolation of O→P coordinated 1-chloro-7-(t-butoxymethyl)-3H-2,1-benzoxaphosphole (1) as the result of the cyclization type reaction of dichlorophosphines L 1 PCl 2 . The hydrolysis of compounds 1–3 as well as the preparation of phosphanes L 2 PH 2 (7), L 3 PH 2 (8), L 2 PH(SnMe 3 ) (9) and L 3 PH(SnMe 3 ) (10) is also discussed. The presence of N→P coordination enabled the isolation of N→P coordinated diselenoxophosphorane L 3 PSe 2 (11). Compounds 1–11 were characterized by the help of multinuclear NMR spectroscopy, ESI mass spectrometry and the structure of compound 11 was established by X-ray diffraction analysis.