Compounds of Formula (1) are disclosed. Cb is a carbocyclic or heterocyclic group having an atom within the cyclic structure selected from C, N, Si, and Cr and singly bound to A. A is CR, COR, CSR, CNR2, CCN, CCONR2, CNO2, CNNAr, CX1, or N. Cr is a chromophore having a substantially planar cyclic structure. The compounds function as nanometer-scale rotary molecular motors powered and controlled by light energy. The design of the molecular motor devices is flexible so that the rotary direction, drive light wavelength, and other physical characteristics can be varied. The compounds can be chemically functionalized to allow it to be integrated into or attached to a variety of structures. The device can be used in applications where mechanical power, positional control, and information encoding are to be generated at the size scale of individual molecules.