A series of cyclic (PRZ, R = Ph, cyclohexyl, F, 2,6-dimethylphenoxy and pyrrolidinyl and Z = 5-substituted dipyrromethane, functionalised 5-diphenyldipyrromethane) and acyclic ((PRx(Z)3-x), x = 0-2, R = Ph, Z = pyrrole or indole) N-pyrrolyl phosphines have been synthesised. Their coordination to Pt has been investigated and the free energies of activation 80* for Pt-P rotation of Pt(II) complexes of phenyl and 2,6-dimethylphenoxy substituted cyclic N-pyrrolyl phosphines have been calculated. Their 1t-accepting and a-donating properties have also been investigated by synthesising their rhodium chlorocarbonyl complexes and their selenides respectively. The cyclic N-pyrrolyl phosphines are stronger 1tacceptors and weaker a-donors than their acyclic analogues. These observations were supported by DFT calculations.