Fabrication of microscale organic photonic integrated circuits (μ-OPIC) from two electronically different flexible crystals via a mechanophotonics approach is demonstrated here. The experiments focus on the mechanical micromanipulation of orange-emitting (E)-1-(4-(dimethylamino)-phenyl) iminomethyl-2-hydroxyl-naphthalene (DPIN) and green-emitting (E)-1-(4bromo)iminomethyl-2-hydroxyl-naphthalene (BPIN) crystals with atomic force cantilever tip. The flexibility of these crystals originate from molecular H-bonding, CH•••π, and π•••π stacking interactions. These mechanically compliant crystals form exceedingly bent and photonically relevant reconfigurable geometries during micromanipulation, including three μ-OPICs.Remarkably, these μ-OPICs operate through passive-, active-waveguiding and energy transfer mechanisms. Depending upon the crystal's electronic nature (either BPIN or DPIN) receiving the optical signal input, the circuit executes mechanism-selective and direction-specific optical outputs. The presented proof-of-principle concepts can be used to fabricate complex photonic circuits with diverse, flexible crystals performing multiple optical functions.

With the rising concerns about global cybersecurity, safe data transduction that would be impervious to cyber attacks necessitates an immediate shift from electron-based to light-based devices. Here, the construction of silicon-free, all-organic photonic integrated circuits by micromanipulation of organic crystals of two mechanically different materials with complementary optical properties, one of which is plastically bendable, is described. The resulting optical circuits are endowed with mechanical reconfiguration at two levels: first, the individual components can be processed into arbitrary shape before integration into the circuit, and second, the circuit itself is reconfigurable even after it is fabricated. The results do not only demonstrate the infinite structural variations in optical microstructures one can build by using organic crystals, but they also show that deformable lighttransducive organic crystals carry an untapped potential for lightweight all-organic optical minicircuitry.

Precise mechanical processing of optical microcrystals involves complex microscale operations viz. moving, bending, lifting, and cutting of crystals. Some of these mechanical operations can be implemented by applying mechanical force at specific points of the crystal to fabricate advanced crystalline optical junctions. Mechanically compliant flexible optical crystals are ideal candidates for the designing of such microoptical junctions. A vapor‐phase growth of naturally bent optical waveguiding crystals of 1,4‐bis(2‐cyanophenylethynyl)benzene (1) on a surface forming different optical junctions is presented. In the solid‐state, molecule 1 interacts with its neighbors via CH⋅⋅⋅N hydrogen bonding and π–π stacking. The microcrystals deposited at a glass surface exhibit moderate flexibility due to substantial surface adherence energy. The obtained network crystals also display mechanical compliance when cut precisely with sharp atomic force microscope cantilever tip, making them ideal candidates for building innovative T‐ and Δ‐shaped optical junctions with multiple outputs. The presented micromechanical processing technique can also be effectively used as a tool to fabricate single‐crystal integrated photonic devices and circuits on suitable substrates.

We report the construction of an organic crystal multiplexer using three chemically and optically different acicular, flexible organic crystals for a broadband, visible light signal transportation. The mechanical integration of a highly flexible crystal waveguide of (Z)-2-(3,5-bis(trifluoromethyl)phenyl)-3-(7-methoxybenzo-[c][1,2,5]thiadiazol-4-yl)acrylonitrile (BTD2CF 3 ) displaying bright yellow (λ 1 ) fluorescence with blue-emitting (λ 2 ) BPP and cyan emitting (λ 3 ) DBA crystals using AFM-tip provides a composite organic crystal multiplexer. The constructed hybrid single crystal multiplexer effectively transduces three optical signals (λ 1 + λ 2 + λ 3 ) covering the 420-750 nm region as a composite output signal. The presented proof-of-principle experiment demonstrates the real potential of organic flexible crystal waveguides for visible light communication technologies.

Fabrication of organic photonic integrated circuits (OPICs) greatly relies on crystalline materials with high mechanical flexibility and fluorescence (FL). Realizing an efficient OPIC with multiple photonic functions suitable for practical applications depends on creating complex circuit architectures. The mechanical and optical functions of crystals are susceptible to subtle differences in the molecular packing and, more importantly, the type of intermolecular interactions. Herein, an organic crystal (E)‐1‐(4‐(iodo)phenyl)iminomethyl‐2‐hydroxyl‐naphthalene (IPIN) exhibiting high flexibility under mechanical stress, bright green FL, and selective self‐absorbance of the blue part of its broadband FL signal is reported. IPIN microcrystal transduces its FL effectively even in its bent geometry. The significant crystal‐surface adhesion energy facilitates the micromechanical fabrication of a triply‐bent waveguide using a mechano(crystal)photonic approach, which is later integrated with a singly‐bent waveguide to create a unique OPIC. This futuristic OPIC delivers excitation position‐dependent and direction‐specific long‐pass‐filtered narrowband optical signals with different split ratios.