Synthetic materials can change shape in response to stimuli, with mechanisms reported so far based on the induction of disorder in a pre-organized molecular system. By contrast, harnessing molecular motion by transducing the work of molecular machines is energetically more effective and can mediate functional complexity, as exemplified in biological systems. Here, we show that the power strokes operated by a light-driven molecular motor at the nanoscale can be transduced into the repeated back-and-forth swaying motion of a polymer at the macroscopic length scale. The synchronization of molecular motors, as governed by the energetic landscape of the rotary cycle, is essential to this transduction. Combining synchronization in time with orientation in space allows transducing one molecular rotation into one macroscopic swaying motion using a mechanism that shows analogy with reciprocating pumps. Making materials operate through a variety of sophisticated transduction modes will be critical for the field of autonomous soft robots.