Using all letters

                                                                           phototrophic

                                                                            phototropic

                                                                              trophic

                                                                          The other words:

                                                                             cirrhotic

                                                                             citicorp

                                                                              citric

                                                                              cohort

                                                                               coopt

                                                                              critic

                                                                              crotch

                                                                               hitch

                                                                              hootch

                                                                            hotchpotch

                                                                              octopi

                                                                               optic

                                                                               ortho

                                                                              photic

                                                                               photo

                                                                               picot

                                                                               pipit

                                                                               pitch

                                                                              portico

                                                                              proctor

                                                                               rotor

                                                                               thoro

                                                                               thorp

                                                                               thrip

                                                                              tictoc

                                                                              tiptop

                                                                               tooth

                                                                               topic

                                                                               torch

                                                                               torii

                                                                              torpor

                                                                             trichroic

                                                                              tricot

                                                                               troop

                                                                              tropic

                                                                              troppo

                                                                               troth