Abstract: Chromophores having two-photon or other multi-photon absorptivity. The chromophores are based on a structure of four stilbenoid groups attached to a paracyclophane core, where each stilbenoid group comprises a nitrogen-containing organic group attached by its nitrogen atom to a stilbenoid arm. In particular embodiments, at least one of the stilbenoid groups includes a sulfonium, ammonium, selenium, iodonium or phosphonium moiety. The chromophores have utility as photo-polymerization initiators and two-photon fluorophores for biological imaging.