Hydroxymethylphosphines are compounds containing P-CH₂-OH functional groups. They have numerous applications, of which three types were explored in this project. The cross-linking ability of tris(hydroxymethyl)phosphine (THP) was investigated for use as a fixative for biological samples for visualisation by scanning electron microscopy (SEM). THP has similar cross-linking ability to glutaraldehyde, the most commonly used fixative for SEM samples. Samples fixed with THP were compared with samples fixed with glutaraldehyde and an unfixed sample, under the SEM. THP appears to have a similar effect on the preservation of the samples, and seems to be successful as a fixative. The bonding between Ph₂P(S)CH₂OH and diiodine was investigated. The resulting adduct was unable to be crystallised. It was partially characterised by ³¹P NMR and IR spectroscopy. The related compound, Ph₃PS.I₂ was synthesised successfully and characterised by ³¹P NMR and IR spectroscopy. The ability of THP to immobilise compounds to solid supports, in the interest of immobilising fluorescent compounds was investigated. THP was used to immobilise N-(2-aminoethyl)-1,8-naphthalimide onto aminopropyl silica, and analysed under UV light. The resulting solid however, fluoresced only slightly. The reaction between Ph₂P(CH₂OH) ₂Cl and N-(2-aminoethyl)-1,8-naphthalimide was also investigated, but the product was unable to be crystallised.