Polysiloxanes were functionalized for Langmuir-Blodgett (LB) deposition of films for optical and bioelectronic applications. Azo dye chromophores give second-harmonic generation and phosphatidylcholine (PC) side-groups yield bilayers suitable for inclusion of active proteins. The polymeric forms are better LB materials than their low molecular mass analogues. One of the azo dye functionalized polymers forms LB films of exceptional clarity; waveguide losses for 633 nm light were measured at around 2.5 dB cm-1 in a 1.3 mum thick film. Bilayers of the PC functionalized polymer have low-field conductivities of the order of 10(-9) S m-1, with a transition to a probable space-charge-limited region and eventual breakdown at above 1.5 x 10(-8) V m-1. Absorption measurements indicate that bacteriorhodopsin remains active when mixed with the PC functionalized polymer.