Abstract: Psoralen compounds are synthesized which have substitutions on the 4, 4', 5', and 8 positions of the psoralen, which permit enhanced binding to nucleic add of pathogens. Higher psoralen binding levels and lower mutagenicity are described, resulting in safer, more efficient, and reliable inactivation of pathogens in blood products. The invention contemplates inactivation methods using the new psoralens which do not compromise the function of blood products for transfusion. In particular compounds with primary aminoalkyl substitutions on the 4' or 5' positions of psoralen are used to inactivate pathogens in blood products such as platelets.