Phosphine-catalyzed chemodivergent reactions of para-quinone methides (p-QMs) affording a wide variety of diarylmethyl thioether derivatives have been reported. In the transformation presented in this work, P(4-FC6H4)3 catalyzed the direct 1,6-addition of p-QMs with thiols, whereas P(4-MeC6H4)3 promoted the tandem addition/self-aldol condensation reactions of p-QMs with 1,4-dithiane-2,5-diol. Moreover, some of the obtained products were screened against cancer cell lines HepG2, NB4, and K562, and one was found to inhibit the proliferation of all the tested cancer cell types